$A$ is the brother of $R$. $C$ is the mother of $B$. $M$ is the sister of $C$. How is $M$ related to $B$?

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

$K$ is the brother of $N$ and $X$. $Y$ is the mother of $N$ and $Z$ is the father of $K$. Which of the following statements is not definitely true?

Following questions are based on the information provided below:
$A \times B$ means $A$ is mother of $B$.
$A - B$ means $A$ is brother of $B$.
$A + B$ means $A$ is sister of $B$.
$A \div B$ means $A$ is father of $B$.
Which of the following means $F$ is paternal grandfather of $H$?

$P$ 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?

$A$ girl introduced a boy as the son of the daughter of the father of her uncle. The boy is the girl's: