A 7D vehicle driver notices that a student is unbuckling their seatbelt while the vehicle is in motion. What is the driver's most appropriate immediate action?

1. Ignore the behavior as long as the student remains seated.
2. Pull the vehicle over in a safe location and ensure the student is properly restrained before continuing.
3. Report the student to their school principal at the end of the route.
4. Verbally reprimand the student loudly to deter other students from doing the same.