The answer is D, a beautiful place for a concert. The appositive is a noun or a noun phrase that renames the another noun right beside it. It is usually surrounded with commas, that is how it is mostly and most easily recognized. The answer cannot be A, because that is a part of a sentence, not a phrase. B is a noun phrase, but not appositive. C is just a noun. So we are left only with D, which is the correct answer.