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

$C$ is $A's$ father's nephew. $D$ is $A's$ cousin but not the brother of $C$. How is $D$ related to $C$?

Pointing to a lady,a man said,"The son of her only brother is the brother of my wife." How is the lady related to the man?

Pointing to a man in a photograph,a woman said,"His brother's father is the only son of my grandfather." How is the woman related to the man in the photograph?

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 $B$?

Given that:
$1.$ $A$ is brother of $B$.
$2.$ $C$ is father of $A$.
$3.$ $D$ is brother of $E$.
$4.$ $E$ is daughter of $B$.
Then,uncle of $D$ is