To determine which pair of objects will have an attractive electric force, we need to consider the types of charges involved.
- Pair A: Charge -2 and Charge -1 (both negative) - Repulsive
- Pair B: Charge -3 and Charge +1 (one negative and one positive) - Attractive
- Pair C: Charge +3 and Charge +1 (both positive) - Repulsive
- Pair D: Charge +1 and Charge +2 (both positive) - Repulsive
The only pair that has one positive and one negative charge, resulting in an attractive force, is Pair B (Charge -3 and Charge +1).
Therefore, the correct response is Pair B.