Pointing to the lady in the photograph,Mrinalini said,"Her son's father is the only son-in-law of my mother". How is Mrinalini related to the lady?

$I.$ $A , B , C , D , E$ and $F$ are six members of a family.

$II.$ One couple has parents and their children in the family.

$III.$ $A$ is the son of $C$ and $E$ is the daughter of $A$.

$IV.$ $D$ is the daughter of $F$ who is the mother of $E$.

Who are the male members in the family?

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 $F$. What is the profession of $B$?

$P$ is the brother of $Q$. $M$ is the sister of $Q$. $T$ is the brother of $P$. How is $Q$ related to $T$?

There are six persons $A, B, C, D$ and $E, F$. $C$ 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. How is $F$ related to $E$?

$A \div B$ means $A$ is the father of $B$,$A - B$ means $A$ is the wife of $B$,$A \times B$ means $A$ is the brother of $B$,$A + B$ means $A$ is the daughter of $B$.
If $P \div R + S + Q$,which of the following is true?