A thin, uniformly charged rod $28\mathrm{.}1-cm$ long is bent into a semicircle. The total charge on the rod is $0\mathrm{.}589C.$ What is the magnitude of the electric field at the center of the semicircle?

$4\mathrm{.}21{10}^5\frac{N}{C}$

$5\mathrm{.}06{10}^5\frac{N}{C}$

$6\mathrm{.}32{10}^5\frac{N}{C}$

$13\mathrm{.}2{10}^5\frac{N}{C}$

$8\mathrm{.}43{10}^5\frac{N}{C}$