What is the concept of circular motion?

I- The circular motion is the type of motion in which the particle has a circumference as a trajectory (Linear Motion) and the radius of rotation simultaneously sweeps a central angle (Angular Motion).
II- The relationship between the arc S and the central angle θ is given by: S = θ R.
III- The radian is the central angle whose corresponding arc length is numerically equal to the radius.
IV- In one revolution (1 rev), the particle describes the length of the circumference as an arc S.
a) Only I and II are correct.
b) Only II and III are correct.
c) Only III and IV are correct.
d) All statements are correct.