Find the Length of the Polar Curve $$r = 3 \cos \theta , 0 \leq \theta \leq \frac { 3 \pi } { 4 }$$

Multiple Choice

Find the length of the polar curve.
$$r = 3 \cos \theta , 0 \leq \theta \leq \frac { 3 \pi } { 4 }$$

A) $\frac { 9 \pi } { 11 }$
B) $\frac { \pi } { 3 }$
C) $\frac { 9 } { 4 }$
D) $\frac { 9 \pi } { 4 }$
E) None of these