Sketch the Region Whose Area Is Given by the Definite $\int _ { - 3 } ^ { 3 } \sqrt { 9 - x ^ { 2 } } d x$

Multiple Choice

Sketch the region whose area is given by the definite integral and then use a geometric formula to evaluate the integral. $\int _ { - 3 } ^ { 3 } \sqrt { 9 - x ^ { 2 } } d x$

A) $9 \pi$
B) $\frac { 9 \pi } { 4 }$
C) $\frac { 9 } { 2 }$
D) $\frac { 9 \pi } { 2 }$
E) none of the above