Since the ball isn't moving under its own power, its speed must necessarily decrease after it has been accelerated (either by the pitcher or the batter).
Any increase in speed would be almost instantaneous, when one considers the time taken to pitch or hit a ball, compared with the time the ball is in the air, either between the mound and the plate or else between the plate and the ball's terminus.
If we could these very short acceleration periods, then we must start the ball at zero, have a short and sharp increase in speed, followed by a longer slight decrease. This is the pitch. Then the speed drops to zero (when the bat stops it), followed by another short and sharp increase, followed by a long slight decrease. Then the ball stops (by hitting the ground or being caught).
Assuming we consider the acceleration periods, only (B) come close. But since the pitch is in the air longer than in the pitcher's hand, (B) is not accurate.
If we include the drop to zero speed, then (A) would be best. But (A) shows the ball speeding up after it leaves the pitcher's hand, which is impossible. So (A) can't work.
And the lack of acceleration (this is a ball, not a rocket) eliminates (C) and (D).
I would not accept any of these plots as reasonable.
Eliz.
