$A$ and $B$ are a married couple. $X$ and $Y$ are brothers. $X$ is the brother of $A$. How is $Y$ related to $B$?

$Q$ is the brother of $R$; $P$ is the sister of $Q$; $T$ is the brother of $S$; $S$ is the daughter of $R$. Who are the cousins of $Q$?

$A$ 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. Which of the following are the two married couples?

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

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 $F$. How is $D$ related to $F$?

$P$ 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?