(a) The ALJ may grant a motion for discovery only if he/she finds that the discovery sought—

(1) Is necessary for the expeditious, fair, and reasonable consideration of the issues;

(2) Is not unduly costly or burdensome;

(3) Will not unduly delay the proceeding; and

(4) Does not seek privileged information.

(b) The burden of showing that discovery should be allowed is on the party seeking discovery.

(c) The ALJ may grant discovery subject to a protective order.