a. Non-static member classes must have either default or public accessibility.
b. All nested classes can declare static member classes.
c. Static member classes can contain non-static methods.
d. All nested classes can be declared static.
Answer:
c. Static member classes can contain non-static methods.
Explanation
Non-static member classes, unlike top-level classes, can have any accessibility modifier. Static member classes can only be declared in top-level or nested static member classes and interfaces. Only static member classes can be declared static.
