Technician a Says That a Series Hybrid Electric Vehicle (SEV)

Technician A says that a series hybrid electric vehicle (SEV) technology is used in some transit buses. Technician B says that rang-extended electric vehicles (REEV) are designed to primarily use electric drive. most commercial hybrid hydraulic vehicles use a diesel engine as the primary power source. Technician B says that most commercial hybrid electric vehicles use a diesel engine as the primary power source. Who is correct?

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