$P$ is the brother of $Q$ and $R$. $S$ is $R$'s mother. $T$ is the father of $P$. Which of the following statements cannot be definitely true?

$A$ 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 is definitely a group of male members?

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?

$A$ family consists of six members $P, Q, R, X, Y,$ and $Z$. $Q$ is the son of $R$ but $R$ is not the mother of $Q$. $P$ and $R$ are a married couple. $Y$ is the brother of $R$. $X$ is the daughter of $P$. $Z$ is the brother of $P$.
Who is the brother-in-law of $R$?

$A + B$ means $A$ is the daughter of $B$; $A - B$ means $A$ is the husband of $B$; $A \times B$ means $A$ is the brother of $B$.
If $P \times Q + R$,which of the following is true?

Rahul's mother is the only daughter of Monika's father. How is Monika's husband related to Rahul?