Question about inheritence of a template class and the usage of this

Question

I have this little sample class here:

#include <iostream>

class A {
protected:
    void method_a() {
        std::cout << "Hello World" << std::endl;
    }
};

template <class T>
class B : public A {
public:
    void method_b() {
        method_a();
    }
};

template <class T>
class C : public B<T> {
public:
    void method_c() {
        method_a(); // the line the question is about
    }
};

int main() {

    C<int> c;
    c.method_c();
}

If I compile this using g++ I get this error:

$ tmp g++ -std=c++17 test.cpp
test.cpp: In member function ‘void C<T>::method_c()’:
test.cpp:22:9: error: there are no arguments to ‘method_a’ that depend on a template parameter, so a declaration of ‘method_a’ must be available [-fpermissive]
         method_a();
         ^~~~~~~~
test.cpp:22:9: note: (if you use ‘-fpermissive’, G++ will accept your code, but allowing the use of an undeclared name is deprecated)

However if I change the method_c to the following it works:

void method_c() {
    this->method_a();
}

I am having trouble understanding the compiler behaviour here. Why do I need to add a this here? Is this a general case for c++ and inheriting multiple times? I do not recall having encountered this problem before.

Side note: I actually encountered this in a more complex example but for simplicity I tried to find a minimum working example