How Should the Conduit or an Extension Be Aligned with the Grooved

How should the conduit or an extension be aligned with the grooved roller?

A) These parts are preset in the factory and must not be changed in the field.
B) They should be lightly touching the rollers so that the welding current can flow down the wire to the welding gun.
C) They should be ½ in. (13 mm) from the grooves in the roller to prevent arcing.
D) These parts should be set as close as possible without touching the roller.