Problem $12-(20$ Points$)$: $(5$ pts each$)$

At UNIST, students were taught how to determine gain and impedances of given amplifier $\backslash (\backslash$boldsymbol$\{$b y$\}\backslash )$ inspection. You do not have to show your work. Just write down the answers by inspection. If you are able to do this, you can save lots of time in determining first order calculation. Determine the output impedance, Rout for the schematics shown below. Assume all of the transistors operate in saturation and $\backslash ($ g$\_\{$m$\}$ r$\_\{$o$\}\backslash$gg $1\backslash ).$

$($a$)$

$($b$)$

$($d$)$