Which is true about an anonymous inner class?

ANS:C - It can extend exactly one class or implement exactly one interface.

Option C is correct because the syntax of an anonymous inner class allows for only one named type after the new, and that type must be either a single interface (in which case the anonymous class implements that one interface) or a single class (in which case the anonymous class extends that one class). Option A, B, D, and E are all incorrect because they don't follow the syntax rules described in the response for answer Option C.