The topic of this question is multiple-choice questions, and the examples are excluded as follows:

Case 1: T is all odd sets and v is all even sets, then both are closed sets.

Case 2: T is a single element set composed of 1, and V is a set composed of other remaining elements, so T is closed, but-1 is in V, 1 is not in V, and V is not closed.

So the answer is a.