$\mathrm{A} C D$ Has a Diameter Of $12.0 \mathrm{~cm}$ If The Has

Multiple Choice

$\mathrm{A} C D$ has a diameter of $12.0 \mathrm{~cm}$ . If the $\mathrm{CD}$ is rotating at a constant angular speed of 20.0 radians per second, then the frequency of the rotational motion is

A) $2.14 \mathrm{~Hz}$ .
B) $4.50 \mathrm{~Hz}$ .
C) $3.83 \mathrm{~Hz}$
D) $4.89 \mathrm{~Hz}$ .
E) $3.18 \mathrm{~Hz}$