When object a collides with object b and bounces back, its final momentum is its initial momentum.
a. greater than
c. in the same direction as
b. less than
d. in the opposite direction of

When object A collides with object B and bounces back, its final momentum is in the opposite direction of its initial momentum. The correct option among all the options that are given in the question is the last option or option "d". This type of collision is elastic in nature as the ball bounces back and so the momentum has to be in the opposite direction of the initial momentum.