A person may legally ride in the back of a pickup truck when: The sides of the pickup bed are at least 24 inches high. The back of the pickup is covered with a camper shell. In a secured seat and while using an approved safety belt.

C.  In a secured seat and while using an approved safety belt.

Explanation:

Pick up trucks are manufactured for the purpose of transporting goods or other equipment but not for the transportation of humans. While riding at the back of a pickup truck can seem enticing, if appropriate measures are not considered, then there would likely be an accident for the driver might take a sharp turn which could cause the passengers behind harm.

One of the laws for riding in the back of a pickup truck is possessing a federally-approved restraint system which protects the rider in the bed of the truck. So, the rider should seat in a secured seat with an approved safety seat belt to keep him protected in the event of a crash.