Technician a says that the burning of the air-and-fuel mixture in the cylinder is called fuel activation. technician b says that the basic function of the upper-end components is to control the flow of air-and-fuel mixture into the engine and the flow of exhaust gases out of the engine after combustion. who is right? a. both technicians a and b b. technician a only c. neither technician a nor b d. technician b only