Pointing to a photograph,a man said,"$I$ have no brother or sister,but that man's father is my father's son." Whose photograph was it?

$A$ man said to a lady,"Your mother's husband's sister is my aunt." How is the lady related to the man?

$M$ is $N$'s brother. $S$ is $D$'s mother and $M$'s aunt. How is $D$ related to $M$?

Pointing to a lady,a man said,"The son of her only brother is the brother of my wife." How is the lady related to the man?

$A + B$ means $A$ is the daughter of $B$; $A \times B$ means $A$ is the son of $B$; and $A - B$ means $A$ is the wife of $B$. If $Z \times T - S \times U + P$,what is $U$ to $Z$?

$A$ family consists of six members $P, Q, R, S, T,$ and $U.$ There are two married couples. $Q$ is a doctor and the father of $T.$ $U$ is the grandfather of $R$ and is a contractor. $S$ is the grandmother of $T$ and is a housewife. There is one doctor,one contractor,one nurse,one housewife,and two students in the family. What is the profession of $P?$