Correct Answer: R is T's mother's brother

Solution : Given:
Q + R means Q is the wife of R
R – S means R is the brother of S
P × Q means P is the father of Q
S ÷ T means S is the mother of T

According to the given information, the family tree will be as follows –

Here, the quadrilateral represents the male, and the circular figure represents the female in the figure.
Let's check the options –
First option: T is the son of S – From the above family tree, it is evident that T can either be the son or daughter of S as T's gender is undefined. Therefore, this option is incorrect.
Second option: Q is the sister of S – From the above family tree, it is evident that R is the brother of S and Q is R's wife. So, Q is the sister-in-law of S. Therefore, this option is incorrect.
Third option: R is T's mother's brother – From the above family tree, it is evident that S is the mother of T and R is the brother of S. So, R is T's mother's brother. Therefore, this option is correct.
Fourth option: P is the father of R – From the above family tree, it is evident that P is the father of Q and Q is R's wife. So, P is the father-in-law of R. Therefore, this option is incorrect.

Hence, the third option is correct.