The Commission shall review the request and responsive comments. The Commission shall either:

(a) Approve the request to modify the market dominant and competitive product lists;

(b) Institute further proceedings to consider all or part of the request if it finds that there is substantial likelihood that the modification is inconsistent with statutory policies or Commission rules, and explain its reasons for not approving the request to modify the market dominant and competitive product lists;

(c) Provide an opportunity for the Postal Service to modify its request; or

(d) Direct other action as the Commission may consider appropriate.