The correct answer is c) maintain correct posture
You should always do warm ups before exercises to get your muscles ready and body flexible.
You should never lift objects with your upper back even if you have lower back pain, you should just avoid lifting anything if you have any back pain.
Limiting the amount of exercise you do per week might help to prevent back pain but it entirely depends on what exercises you do.
Only maintaining correct posture at all times is an effective preventative measure against back pain.
