Technician A says that a generic HH-EST can be used in place of a PC to read a truck data bus.Technician B says that a disadvantage of generic HH-ESTs is that not all OEMs support their software systems.Who is correct?

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

Technician A is correct because a generic Hand-Held Electronic Service Tool (HH-EST) can indeed be used to read data from a truck's data bus, serving as an alternative to using a PC. Technician B is also correct because one of the disadvantages of using generic HH-ESTs is that they may not be compatible with all Original Equipment Manufacturer (OEM) software systems, limiting their functionality with certain vehicles.