Who is the DNS resolver for your client machine in the request below?

$$ a$.$ The IP address $72\mathrm{.}163\mathrm{.}5\mathrm{.}201$

$$ a$.$ The IP address $72\mathrm{.}163\mathrm{.}5\mathrm{.}201$

$$ b$.$ The server nst$.$cisco.com

$$ c$.$ The local IP address $127\mathrm{.}0\mathrm{.}0\mathrm{.}53$

$$ d$.$ The server www$.$cisco.com