A)  Can be connected to either

B)  Can not be connected to an equipment grounding bus

C)  Must be connected to the neutral bus

D) Can be connected to a lug on the enclosure
E) Can be connected to an equipment grounding bus with a proper jumper

Answer:  E

NEC 250.24(4) permits the grounding electrode conductor to be connected to the ground bus in the panelboard if there is a properly sized wire/jumper from the grounding bus to the neutral bus. Using the panelboard housing as a conductor is not permitted.

250.24 Grounding Service-Supplied Alternating-Current Systems

(A) System Grounding Connections.

A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(1) through (A)(5).

(4) Main Bonding Jumper as Wire or Busbar.

Where the main bonding jumper specified in 250.28 is a wire or busbar and is installed from the grounded conductor terminal bar or bus to the equipment grounding terminal bar or bus in the service equipment, the grounding electrode conductor shall be permitted to be connected to the equipment grounding terminal, bar, or bus to which the main bonding jumper is connected.