I think it is C) the resting position of the wave.
maximum speed of cheetah is

speed of gazelle is given as

Now the relative speed of Cheetah with respect to Gazelle


now the relative distance between Cheetah and Gazelle is given initially as "d"
now the time taken by Cheetah to catch the Gazelle is given as

so by rearranging the terms we can say


so above is the relation between all given variable
Answer:
The force exerted by X on Y is F to the right, and the force exerted by Yon X is F to the left.
Explanation:
There are two objects X and Y. Mass of object X is 2M, that is moving with a speed of
and that of object Y is M that is moving with a speed of
.
When both of the objects collide, the magnitude of the forces F the objects exert on each other is equal to :
The force exerted by X on Y is F to the right, and the force exerted by Yon X is F to the left using Newton's third law of motion. Hence, the correct option is (c).