Which of the following sets is non-empty?

Which of the following statements is true?

Let $A = \{a, b, c\}, B = \{b, c, d\}, C = \{a, b, d, e\}$. Then $A \cap (B \cup C)$ is

If $A = \{a, b\}$,$B = \{c, d\}$,$C = \{d, e\}$,then the set $\{(a, c), (a, d), (a, e), (b, c), (b, d), (b, e)\}$ is equal to:

If $S$ and $T$ are two sets such that $S$ has $21$ elements,$T$ has $32$ elements,and $S \cap T$ has $11$ elements,how many elements does $S \cup T$ have?

In a survey of a town,it was found that $65 \%$ of the people surveyed watch the news on $T.V.$,$40 \%$ read a newspaper,and $25 \%$ read a newspaper and watch the news on $T.V.$ What percent of the people surveyed neither watch the news on $T.V.$ nor read a newspaper?