Find the Area of the Specified Region $r = 3 \cos \theta$

Multiple Choice

Find the area of the specified region.
-Shared by the circles $r = 3 \cos \theta$ and $r = 3 \sin \theta$

A) $\frac { 3 } { 2 } ( 2 - \sqrt { 2 } )$
B) $\frac { 9 } { 4 } \pi$
C) $\frac { 3 } { 8 } ( 4 \pi - 3 \sqrt { 3 } )$
D) $\frac { 9 } { 8 } ( \pi - 2 )$