Answer:
C) Compensatig wage differentials
Explanation:
Driving a truck is not an easy job. It is uncomfortable, usually requires long-hours. Truck drivers frequently have to work at night, pull all-nighters. They are prone to health issues like backache, etc.
They have to be offered a higher wage for accepting that kind of job, and that is what compensating wage differentials are about: it consists in offering higher wages for unpleasant jobs, hence the adjective "compensating", it is a wage that compensates the unpleasantness.
