Technician a Says That CAN L (-)And (Chassis)ground Are of Equal

Multiple Choice

Technician A says that CAN L (-) and (chassis) ground are of equal voltage potential.Technician B says that modules networked to a J1939 bus are designed to identify the difference between CAN H (+) and CAN L (-) in message packet without reference to chassis ground.Who is correct?

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