How does mass affect the force of gravity between 2 objects?

Force due to gravity increases on increasing the masses and decreases on decreasing the masses.  

Explanation:

The force due to gravity (F) acting between any two given bodies can be expressed as,

Here,

G = gravitational constant

= mass of the first body

= mass of the second body

separation between the bodies

It is clear from the above expression that the force due to gravity acting between the two bodies is directly proportional to the product of the masses of the bodies.

the answer is a. at the equator