Technician A & B both are correct.
Step-by-step explanation:
A PCM stands for powertrain control module which is used in electronic fuel-injection system to control the working of fuel injectors. So, Technician A is correct. A TBI stands for throttle-body-injection which is used to inject the fuel into the air above the throttle plate of engine. That's why Technician B is also correct.
Fuel tank consists of electronic fuel pump. Computer control fuel pump relay and fuel-pressure regulator. Fuel pump speed is controlled by PCM. Technician B says that a TBI injector squirts fuel above the throttle into air at atmospheric pressure.