Which of the following Venn diagrams corresponds to the statement "All mothers are women"? ($M$ is the set of all mothers,$W$ is the set of all women)

Which of the following pairs of sets are disjoint?
$A = \{a, e, i, o, u\}$ and $B = \{c, d, e, f\}$

$A$ class has $175$ students. The following data shows the number of students opting for one or more subjects: Mathematics $100$,Physics $70$,Chemistry $40$; Mathematics and Physics $30$,Mathematics and Chemistry $28$,Physics and Chemistry $23$; Mathematics,Physics,and Chemistry $18$. How many students have opted for Mathematics alone?

If $A = \{ x : x \text{ is an integer and } x^2 - 9 = 0 \}$,$B = \{ x : x \text{ is a natural number and } 2 \leq x < 5 \}$,and $C = \{ x : x \text{ is a prime number } \leq 4 \}$,then $(B - C) \cup A$ is:

If $A$ and $B$ are not disjoint sets,then $n(A \cup B)$ is equal to

If $A$ and $B$ are sets,then $A \cap (B - A)$ is