(B) (C) FTTF. (A) is false since $P(A \cup B)=P(A)+P(B)-P(A \cap B)=0.7$.
(B) is true since $P(A \cup C)=P(A)+P(C)-P(A \cap C)=1$.
(C) is false. In view of Option (B), $C=A^c$ and thus $P(B)=P(B \cap A)+P(B \cap C)$. So, $P(B \cap C) = 0.2 .$
(D) Using (C) it follows that $P(B \cup C)=0.8$.