A very massive object A and a less massive object B move toward each other under the influence of gravity. Which force, if either, is greater

Both are equal.

Explanation:

As per the theory of gravitational force, when two objects will be thrown from same height but of different masses, both will reach the ground at same time.

The force of gravity will act same on both objects.

Simple experiments were done by Sir Isaac Newton to reach out to reach out to this conclusion. Two objects were made to fall free under the influence of gravity, neglecting every other small forces, it was observed irrespective of different masses both reaches the ground at same time.