Technician a Says That Vehicles with Electronic Returnless Fuel Systems

Technician A says that vehicles with electronic returnless fuel systems use pulse width modulation to power the fuel pump and maintain fuel pressure. Technician B says that the electronic returnless fuel system uses a power transistor to control the fuel pump. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B