What are the valid access modifiers for top-level Java classes?

• A. Public, private, protected
• B. Public and default only
• C. Private and protected only
• D. Protected and default only

Answer: (B)

The valid access modifiers for top-level Java classes are indeed public and default (which occurs when no modifier is specified). A top-level class in Java can be public, meaning it can be accessed from any other class in any package. On the other hand, if a class has no access modifier, it is said to have default access, which means it is accessible only to classes within the same package.

The other options include private and protected, which are not valid modifiers for top-level classes. Private restricts access to the containing class, which does not apply to top-level classes since they are not nested within another class. Similarly, protected allows access to subclasses and classes in the same package, but it still cannot be applied to top-level classes for the same reason.

Thus, public and default are the only two applicable access levels for top-level classes in Java, making option B the correct choice.