Find the Area of the Specified Region $r = a \sin \theta$

Multiple Choice

Find the area of the specified region.
-Inside the circle $r = a \sin \theta$ and outside the cardioid $r = a ( 1 - \sin \theta ) , a > 0$

A) $\frac { a ^ { 2 } } { 6 } ( 6 - \pi )$
B) $\frac { a ^ { 2 } } { 6 } ( 4 \pi - 3 \sqrt { 3 } )$
C) $\frac { a ^ { 2 } } { 3 } ( 3 \sqrt { 3 } - \pi )$
D) $\frac { a ^ { 2 } } { 12 } ( 2 \pi - 3 \sqrt { 3 } )$