A CD with a Diameter of 12

Multiple Choice

A CD with a diameter of 12.0 cm starts from rest and with a constant angular acceleration of 1.0 rad/sec² acquires an angular velocity of 5.0 rad/sec. The CD continues rotating at 5.0 rad/sec for 15.0 seconds and then slows to a stop in 12.0 second with a constant angular acceleration. What is the radial acceleration of a point 4.0 cm from the center at the time 15.0 seconds from the start?

A) 0.5 m/s²
B) 1.0 m/s²
C) 1.8 m/s²
D) 2.0 m/s²
E) 2.6 m/s²