Two technicians are discussing disc brake rotor service. Technician A says that the inner races (bearing cups) should be removed from the rotor before it is mounted on the lathe. Technician B says that a non-directional finish on the rotor surfaces can be obtained by using sandpaper. Which technician is correct?
a) technician A
b) technician B
c) both technicians A and B
d) neither technician A nor B