Pointing to a person,a man said to a woman,'His mother is the only daughter of your father'. How was the woman related to the person?

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?

$P$ is the father of $J$. $S$ is the mother of $N$,who is the brother of $J$. $B$ is the son of $S$. $C$ is the sister of $B$. How is $J$ related to $C$?

$P$ is the son of $Q$,while $Q$ and $R$ are sisters. $T$ is the mother of $R$. If $S$ is the son of $T$,which of the following statements is correct?

In a family,there are six members $A, B, C, D, E$ and $F$. $A$ and $B$ are a married couple,$A$ being the male member. $D$ is the only son of $C$,who is the brother of $A$. $E$ is the sister of $D$. $B$ is the daughter-in-law of $F$,whose husband has died.
How is $F$ related to $A$?

There is a family of six persons $A, B, C, D, E,$ and $F$. They are lawyer,doctor,teacher,salesman,engineer,and accountant. There are two married couples in the family. $D$,the salesman,is married to the lady teacher. The doctor is married to the lawyer. $F$,the accountant,is the son of $B$ and brother of $E$. $C$,the lawyer,is the daughter-in-law of $A$. $E$ is the unmarried engineer. $A$ is the grandmother of $F$. Which of the following is one of the couples?