Anil introduces Rohit as the son of the only brother of his father's wife. How is Rohit related to Anil?

Looking at a portrait of a man,Harsh said,"His mother is the wife of my father's son. Brothers and sisters $I$ have none." At whose portrait was Harsh looking?

To find out the answer to the above question,which of the statements can be dispensed with?

Pointing to a boy,Seema said,"He is the son of my grandfather's only child". How is the boy related to Seema?

Study the following information carefully to answer these questions.
$(i)$ $P \times Q$ means $P$ is brother of $Q$.
$(ii)$ $P - Q$ means $P$ is sister of $Q$.
$(iii)$ $P + Q$ means $P$ is father of $Q$.
$(iv)$ $P \div Q$ means $P$ is mother of $Q$.
Which of the following represents $M$ is nephew of $N$?

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 $A$?