What is the difference between .ajax() and .getJSON()

Question

I am trying to understand what the difference between these two? I have read that .getJSON calls .ajax. But what functionally is different? Which would work?

Imagine that you are trying to write a client-side webapp that interacts with the following RESTFUL API that represents an online car catalog: GET /cars - Returns a list of all cars in the catalog

Example response:
{"cars": [
    {"id": 1, "model": "Alice in Wonderland", "make": "Chevy"},
    {"id": 2, "model": "Civic", "make": "Honda"}
]}

POST /cars - Creates a new car based on the given info 

Example request:
{"model": "Wrangler", "make": "Jeep"} 

Example response:
{"id": 3} 

GET /cars/<id> - Returns info about the car with that id 

Example response:
{"id": 1, "model": "Alice in Wonderland", "make": "Chevy"} 

PUT /cars/<id> - Overrides info about the car with the given id with the new data 

Example request:
{"model": "Wrangler", "make": "Jeep"} 

DELETE /cars/<id> - Deletes the car at the given id. The id may be recycled for other cars 

You have been instructed to write some code that:

1. Deletes all cars made by Chevy

2. Modifies the models of all cars written by Jeep to all-caps

   $.ajax({ url: "/cars", type: "GET" }, function(data) {
           data.cars.forEach(function (car) {
               var endpoint = "/car/" + car.id;
               if (car.make == "Chevy") {
                   $.ajax({ url: endpoint, type: "DELETE" });
               } else if (car.make == "Toyota") {
                   var request = {title: car.title.toUpperCase(), make: car.make};
                   $.ajax({ url: endpoint, type: "PUT", data: JSON.stringify(request) });
               }
           });
       });
   
   $.getJSON("/cars", function(data) {
       data.cars.forEach(function (car) {
           var endpoint = "/car/" + car.id;
           if (car.make == "Chevy") {
               $.ajax({ url: endpoint, type: "DELETE" });
           } else if (car.make == "Toyota") {
               var request = {title: car.title.toUpperCase(), make: car.make};
               $.ajax({
                   url: endpoint,
                   type: "PUT",
                   data: JSON.stringify(request),
                   contentType: "application.json"
               });
           }
       });
   });