If the position of a point $s$, is given as a function of angular position, $\theta$, by $s = 10 \sin(2 \theta)$, the velocity, $v$, is

A. $20 \cos (2 \theta)$
B. $20 \sin (2 \theta)$
C. $20 \omega \cos (2 \theta)$
D. $20 \omega \sin (2 \theta)$