Answer :
[tex]The\ volume\ of\ the\ cone:V=\frac{1}{3}\pi r^2H\\\\where\\r-radius\\H-height\\----------------\\\\r=8\ in\ and\ H=12\ in\\\\therefore\\\\V=\frac{1}3{\pi\cdot8^2\cdot12=\frac{1}{\not3_1}\cdot\frac{\not12^4}{1}\cdot64\pi=4\cdot64\pi=\boxed{256\pi\ (in^3)}\\\\Answer:\boxed{C}[/tex]