Answer
(a) Plot B
(b) III
Work Step by Step
(a) We know that if the ball is thrown up in the air with some initial horizontal angle, then its velocity decreases with time. Thus, plot B represents the speed of the ball as a function of time.
(b) We know that the best explanation is option (III) -- that is, the ball's speed decreases during its flight but it doesn't go to zero.
