Consider the finite automation in the following figure.

What is the set of reachable states for the input string $$0011?$$

If $${L_1} = \left\{ {{a^n}\left| {n \ge \left. 0 \right\}} \right.} \right.$$ and $${L_2} = \left\{ {{b^n}\left| {n \ge \left. 0 \right\}} \right.} \right.,$$ consider
$$\left. {\rm I} \right)$$ $$\,\,\,{L_{1 \bullet }}{L_2}$$ is a regular language
$$\left. {\rm II} \right)$$ $$\,\,\,{L_{1 \bullet }}{L_2} = \left\{ {{a^n}{b^n}\left| {n \ge \left. 0 \right\}} \right.} \right.$$
Which one of the following is CORRECT?

The length of the shortest string NOT in the language (over $$\sum { = \left\{ {a,\,\,b} \right\}} $$) of the following regular expression is ____________. $$$a{}^ * b{}^ * \left( {ba} \right){}^ * a{}^ * $$$

Consider the languages $${L_1} = \phi $$ and $${L_2} = \left\{ a \right\}.$$ Which one of the following represents $${L_1}\,L_2^ * UL_1^ * ?$$