$14.$ Determine the shear stress at point $\backslash ($ A $\backslash ),$ which exists in the side $($vertical$)$ wall. Assume the internal shear is $\backslash (10,000\backslash$mathrm$\{$lbs$\}\backslash ).$

A$.40\mathrm{.}32$ psi

B$.90\mathrm{.}73$ psi

C$.148\mathrm{.}9$ psi

D$.181\mathrm{.}5$ psi

E$.$ None of the above

$($Cross$-$section$)$