Technician a Says That Synthetic Lubricants May Be Used in Truck

Technician A says that synthetic lubricants may be used in truck differential carriers but OEMs have yet to authorize extended oil drain intervals.Technician B says that using synthetic gear lubes is cost effective compared to mineral-base gear lube because of greatly increased oil drain intervals and reduced labor.Who is correct?

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