"two positively charged particles are held in place. Another particle with a mystery charge (represented by the question mark) is introduced
and free to move as shown above. If the particle with the mystery charge moves to the right, which of the following must be true and why?

1. The mystery particle has a positive charge, it feels a repulsive force from the two positive particles.

2. The mystery particle has a negative charge, it feels an attractive force from the two positive particles.

3. The mystery particle has a negative charge, it feels a repulsive force from the two positive particles.

4. The mystery particle has a positive charge, it feels an attractive force from the two positive particles