In the given scenario, X and Y are brothers. This means that Y is the brother of X. Z is the sister of X, which means Z is also a sibling of Y. P is the brother of Q, indicating that P is a male. Q is the daughter of Y, making Q the child of Y.

To determine who the uncle of P is, we need to find a person who is a brother of P`s sibling. Since Y is the father of Q, Y is the sibling of P. Therefore, Y is the uncle of P.

Checking the options:

Option 1: Z - Z is not a brother of P`s sibling. Incorrect.

Option 2: X - X is the brother of P`s sibling. Correct.

Option 3: Q - Q is P`s sibling, not the uncle. Incorrect.

Option 4: Y - Y is indeed the uncle of P. Correct.

Therefore, the correct answer is option 4, Y.