$3$ Regular Expressions

Write a regular expression for the following languages.

$($a$)$ All strings of a$\text{'}$s$,$ b$\text{'}$s$,$ and c$\text{'}$s that start with aba.

$($b$)$ All strings of a$\text{'}$s$,$ b$\text{'}$s$,$ and c$\text{'}$s that do not contain more than $1a,1b,$

$1c.$