Stuck in a do while loop and I cant get out

Question

This code is not making it through the second dowhile loop. It seems to be cycling through the default statement and looping back to the option loop. I am not sure what the issue is, but I have rewritten it at least a dozen times, and still I am having trouble with it. What am I leaving out? I'm positive it's something simple that I am just overlooking. Is there an easy way to identify these types of issues?

#include <stdio.h>

int main(void)
{
    int j = 0;
    int i = 0;
    int classSize = 0;
    int position = 0;
    int studentID = 0;
    float average = 0;
    char option = ' ';


    do
    {
        printf("How many students are in the class?\n ");
        scanf("%d", &classSize);
    }while (classSize == 0);

    float class[4][classSize];
    float final[classSize];


    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < classSize; j++)
            class[i][j] = 0;
    }

    for(j = 0; j < classSize; j++)
        final[j] = 0;
    do
    {

        printf ("Please select an option:\n");
        printf ("'A'to add student info one student at a time \n");
        printf ("'D' to display student’s info \n");
        printf ("'T' to display class average for homework\n");
        printf ("'S' to display class average for quizzes\n");
        printf ("'B' to display class average for final exams\n");
        printf ("'W' to display class average for student’s final 
                 grade\n");
        printf ("'Z' to exit program\n");
        scanf("%c\n", &option);

        switch (option)
        {
            case 'a': case 'A':
                if (position < classSize)
                {

                    printf ("Please enter student's number:\n");
                    scanf("%f", &class[0][position] );

                    printf ("Please enter student's homework grade:\n");
                    scanf("%f", &class[1][position] );

                    printf ("Please enter student's quiz grade:\n");
                    scanf("%f", &class[2][position] );

                    printf ("Please enter student's final exam grade:\n");
                    scanf("%f", &class[3][position] );

                    position++;

                }
                else
                    puts("The table is full.\n");

                break;

            case 'd': case 'D':

                printf("Enter student number:\n");
                scanf("%d", &studentID);

                for(j = 0; j < classSize; j++)
                {
                    if (class[0][j] == studentID)
                    {
                        printf ("The student's number is %d. \n", studentID);
                        printf ("The student's homework grade is %.2f.\n", class[1][j]);
                        printf ("The Student's quiz score is %.2f. \n", class[2][j]);
                        printf ("The student's final exam score is %.2f.\n", class[3][j]);
                        printf ("The student's total grade is %.2f. \n",
                            ((class[1].[j]*.5)+(class[2][j]*.1)+(class[3][j]*.4)));

                        break;
                    }
                    else
                        continue;
                    }

                    if (class[0][j] == studentID)
                    {
                        for(j = 0; j < classSize; j++)
                            break;
                    }
                    else
                    {
                        printf("No match\n");
                        break;
                    }
                    break;

            case 't': case 'T':

                average = 0;
                for(j = 0; j < classSize; j++)
                    average = average + class[1][j];

                    average = average / classSize;
                printf("The average homework grade is %.2f\n", average);

                break;

            case 's': case 'S':

                average = 0;

                for(j = 0; j < classSize; j++)
                    average = average + class[2][j];
                    average = average / classSize;
                printf ("The average quiz grade is %.2f\n", average);

                break;

            case 'b': case 'B':

                average = 0;

                for(j = 0; j < classSize; j++)
                    average = average + class[3][j];
                average = average / classSize;
                printf("The average class final grade is %.2f\n", average);
                break;

            case 'w': case 'W':

                average = 0;

                for( j = 0; j < classSize; j++)
                    final[j] = ((class[1][j] * .5) + (class[2][j] * .1) +
                                (class[3][j] * .4));

                for(j = 0; j < classSize; j++)
                    average = average + final[j];
                average = average / classSize;

                printf("The class average is %.2f\n", average);

                break;

            case 'z': case 'Z':

                return 0;

                break;


            default:
            printf("Error...try again\n");
        }
    }
    while(1);

}