Introducing a man,a woman said,'His wife is the only daughter of my father'. How was that man related to the woman?

Pointing to a photograph,Nikita said,'She is the only granddaughter of my grandmother's daughter'. How is the girl in the photograph related to Nikita?

Rahul told Anand,'Yesterday $I$ defeated the only brother of the daughter of my grandmother.' Whom did Rahul defeat?

There are six persons $A, B, C, D, E$ and $F$. $C$ is the sister of $F$. $B$ is the brother of $E$'s husband. $D$ is the father of $A$ and grandfather of $F$. There are two fathers,three brothers,and a mother in the group. Who is the mother?

Pointing to a gentleman,Deepak said,"His only brother is the father of my daughter's father." How is the gentleman related to Deepak?

$A$ 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. Who is the husband of $P$?