- P is the sister of Q, so P and Q are siblings.
- Q is the husband of R, so R is married to Q.
- R is the mother of S, so S is R's child.
- T is the husband of P, so T is married to P.
From this, T is the husband of P, who is the sister of Q. Therefore, T is the brother-in-law of Q. Since Q is S’s parent, T is the uncle of S.
Step 1: Conclusion
T is the uncle of S, so the correct answer is (B).