Consider the following languages.
$$\begin{array}{ll} L_1= \{ wxyx \mid w,x,y \in (0+1)^{+} \} \\ L_2= \{xy \mid x,y \in (a+b)^{*}, \mid x \mid=\mid y \mid, x \neq y \} \end{array}$$
Which one of the following is TRUE?
- $L_1$ is regular and $L_2$ is context- free.
- $L_1$ context- free but not regular and $L_2$ is context-free.
- Neither $L_1$ nor $L_2$ is context- free.
- $L_1$ context- free but $L_2$ is not context-free.