Answer: A. Both Technicians A and B
Explanation: Technician A is right, in most of the bolts you will read the size in the head of it, this is useful because you can only read it when is installed and you do not need to take it away in order to go to a hardware store and buy more, and technician B is also right, the "automotive fasteners" are nuts and bolts (of course, there are different types that may be specially made for cars, but are nuts and bolts)
So both technicians A and B are right.