A V-T Graph Is Drawn for a Ball Moving in One

Multiple Choice

A v-t graph is drawn for a ball moving in one direction.The graph starts at the origin and at t = 6 s the acceleration of the ball is zero.We know that at t = 6 s,

A) the slope of the curve is non-zero.
B) the curve is not crossing the time axis.
C) the velocity of the ball is not changing.
D) the curve is at v = 0,t = 0.