Sample Questions: Java SE 5 and 6, Certified Associate (1Z0-850)

Option A is incorrect because hidden is NOT a valid attribute modifier.
Option B is correct because a well-encapsulated class must have all of its attributes marked private.
Option C is incorrect because hidden is NOT a valid method modifier.
Option D is correct because a well-encapsulated class must hide all internal methods. This is because this is NOT part of the class's public interface.
Option E is incorrect because NOT all attributes require accessor or mutator methods.
Option F is incorrect because exposed is NOT a valid method modifier.