(a) State the pumping lemma for context-free languages (CFLs).

(b) Which of the following are CFLs? Justify your answers.

(i) $\left\{w w^{R} \mid w \in\{a, b\}^{*}\right\}$, where $w^{R}$ is the reverse of the word $w$.

(ii) $\left\{0^{p} 1^{p} \mid p\right.$ is a prime $\}$.

(iii) $\left\{a^{m} b^{n} c^{k} d^{l} \mid 3 m=4 l\right.$ and $\left.2 n=5 k\right\}$.

(c) Let $L$ and $M$ be CFLs. Show that the concatenation $L M$ is also a CFL.