Consider the following three languages:

$L_1=\{a^n{b}^m$:$m$ and $n$ are odd $\}$

$L_2=\{a^n$:$nis$ a positive intecer $\}$

$L_3=\{b^{n!}$:$nis$ a positive integer $\}$

Which of the following is TRUE?

$L_1{L}_2$ is regular.

$L_1-L_3$ is regular.

$(L_1-L_3)(L_1-L_2)$ is regular.

All the other answers are true.