Answer
a) Negative.
b) Hold steady.
c) Zero.
Work Step by Step
a) The torque is negative since the ball is moving clockwise around the pivot point.
b) Since the rod's pivot is frictionless and since the ball is rotating around the pivot point without friction, then the ball will continue rotating at a constant angular speed after the push is stopped.
Thus, the right choice is the ball's angular speed "holds steady".
c) After the push ends, the torque is then zero since the force is disappeared. $\tau= Fr\sin\theta=(0) r\sin\theta =0$
