The lexical analysis for a modern computer language such as java needs the power of which one of the following machine model in a necessary and sufficient sense?

$$S \to aSa\,\left| {\,bSb\,\left| {\,a\,\left| {\,b} \right.} \right.} \right.$$
The language generated by the above grammar over the alphabet $$\left\{ {a,\,b} \right\}$$ is the set of

Which one of the following is FALSE?

Let $${L_1} = \left\{ {{0^{n + m}}{1^n}{0^m}\left| {n,m \ge 0} \right.} \right\},$$
$$\,\,\,{L_2} = \left\{ {{0^{n + m}}{1^{n + m}}{0^m}\left| {n,m \ge 0} \right.} \right\},$$ and
$$\,\,\,\,{L_3} = \left\{ {{0^{n + m}}{1^{n + m}}{0^{n + m}}\left| {n,m \ge 0} \right.} \right\},$$ Which of these languages are NOT context free?