The SI unit for angular velocity is

The correct option is C

$rad/s$

Explanation of the correct option:

(C) rad/s

1. Angular velocity is the rate of angular displacement as a function of time.
2. Angular velocity's SI unit is radians per second (rad/s).

Explanation of the incorrect options:

(A) m/s

1. Speed and velocity both have the SI unit meters per second (m/s).
2. Speed is equal to distance divided by time while velocity is equal to displacement divided by time.

(B) rad

1. Angles are measured using a unit known as radian.
2. 1 radian is approximately equal to $57.3$ degrees.

Thus, the SI unit for angular velocity is rad/s.

Hence, option C is correct.