Final answer:
The pinion and crown gear set determines the output gear ratio in a single-reduction rear axle carrier.
Step-by-step explanation:
The correct answer is c) the pinion and crown gear set.
In a single-reduction rear axle carrier, the pinion and crown gear set determines the output gear ratio. The pinion gear, which is connected to the drive shaft, meshes with the larger crown gear, which is connected to the axle shafts. The number of teeth on the pinion and crown gears determines the gear ratio.
For example, if the pinion gear has 10 teeth and the crown gear has 40 teeth, the gear ratio would be 4:1. This means that for every 4 rotations of the drive shaft, the axle shafts will rotate once.