Volume of an object expressed in spherical coordinates is given by (V = int_0^{ frac{ }{2}} _0^{ frac{ }{3}} _0^1r cos dr d d . ) The value of the integral is _______

• A. ( frac{ sqrt{3}}{2} )
• B. ( frac{1}{ 2} )
• C. ( frac{ sqrt{3}}{2} )
• D. ( frac{ sqrt{3}}{8} )