a) It can only contain one class declaration.
b) It can contain one public class declaration and one public interface definition.
c) It must define at least one public class.
d) It may define at most one public class.
Answer
d) It may define at most one public class.
Explanation:
A valid .java file may define any number of classes or interfaces. However, It can only have at most one public class. Thus, Options A, B, and C are incorrect. Option D is the only correct answer.
