gravity is a force between any two objects with mass. Why doesn't a person feel a gravitational force between him/herself and another person

The force of gravity is not a huge force. Put another way, it is most easily observed when the masses are quite large relatively speaking. The Sun and the earth orbiting around the sun serves to measure the force of gravity. The distance is pretty large but masses are unimaginably larger.

The sum has a mass of 2 * 10^30

The earth has a mass of about 6 * 10^24.

The force of gravity between them is 3.5 * 10^22 Newtons roughtly.

We on the other hand have masses of 70 to 100 kig.

The force between humans is F = 6.67 * 10^-11 * 100 * 100 / 1 meter^2

F_humans = 6.67 * 10 ^ - 7 Newtons.

The equivalent weight is roughly that of a couple of grains of sand. It's just big enough to register on our senses.

Correct answer is C