In which direction does a bag at rest move when a force of 20 newton's is applied from the right?

The bag moves to the left.

This is because of Newton's third law of motion that states:

For every action force on a body, there is an opposite and equal reaction force.

Thus pushing the bag from the right makes it move to the left.

Correct

In the direction of the applied force

real, smaller and upside-down.   so the answer should be b.