Problem $0\mathrm{.}13.$ Evaluate the following integrals:

$a{\displaystyle \underset{|z|=1}{\overset{\phantom{}}{}}}\frac{e^{-z^2}}{z-\frac{i}{2}}dz$

$b{\displaystyle \underset{|z|=1}{\overset{\phantom{}}{}}}\frac{z^3-z^2+z+2}{(2z-3{)}^3}dz$

$c{\displaystyle \underset{|z|=1}{\overset{\phantom{}}{}}}{z}^{4}dz$