Final answer:
Technician B is correct. There are two types of vacuum boosters: a single diaphragm and a tandem diaphragm.
Step-by-step explanation:
The correct answer is Technician B. There are indeed two types of vacuum boosters: a single diaphragm and a tandem diaphragm.
A single diaphragm vacuum booster has a single diaphragm that is connected to the brake pedal and the master cylinder, and it uses the vacuum created by the engine to assist in applying the brakes.
A tandem diaphragm vacuum booster, on the other hand, has two diaphragms connected by a rod. The first diaphragm is connected to the brake pedal, while the second diaphragm is connected to the master cylinder. This design provides a greater boost in braking power.