Given the alphabet $\backslash$Sigma $=\{$rt$,$z$\}[10$m$]($a$)$ Give a regular expression that begins with rt and ends with z$.($b$)$ Give a regular expression that has at most length $2.($c$)$ List the language given by the following regular expression i$.\backslash$sum $+\backslash$cup $\{\backslash$lambda $\}$ ii$.\backslash$lambda $\backslash$cup $($t$+$z$)\backslash$cup $($t$+$z$)^(2)$ iii. t$($a$+$z$)^(**)$