Which of the following statements is true concerning a class.

Select one:

a. In a class, fields can ONLY be primitive data types or existing Java types (from existing Java classes)

b. In a class, fields can ONLY be user-defined types.

c. In a class, fields can be primitive data types, existing Java types, or user-defined types.

d. In a class, fields can ONLY be primitive data types such as int, float, etc.