From the following, select the true statement.

a$.L=\{a^n{b}^n{c}^n|n42\}$ is not context free.

b$.$ If $B$ is context free and $A$ is a subset of $B,$ then $A$ is context free.

c$.$ If $A$ is not context free, then $A$ is also not regular.

d$.$ Intersection of two context free languages is context free.