A pulley of radius 2 m is rotated about its axis by a force \[F=(20t-5{{t}^{2}})\] newton (where \[t\] is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is \[10\,kg{{m}^{2}}\], the number of rotations made by the pulley before its direction of motion is reversed, is:

• A. less than 3
• B. more than 3 but less than 6
• C. more than 6 but less than 9
• D. more than 9