$L_1$ is CFL [ put $a$'s in stack , and pop $a$ with each $b$]]
$L_2$ is CFL [put $b$'s in stack and pop $b$ with each $c$ ]
C) is True.
B) is True. CFL is closed under Union [ $S \rightarrow S_1 \mid S_2$ where $S_1$ is grammar for $L_1$ and $S_2$ for $L_2$]
CFL is not closed under Intersection, so intersection of two CFLs may or may not be CFL. Lets examine:
$L_1 \cap L_2 = \{ a^ib^ic^i , i>0 \}$ which is Context sensitive but not context free [can't match $a$'s,$b$'s and $c$'s with one stack]
So, A) is False.
D) is True.