​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) ​½ in.(13 mm) from the grooves in the roller to prevent arcing.
D) ​Set as close as possible without touching the roller.