In Order for Antitrust Laws to Raise Social Welfare,what Must

In order for antitrust laws to raise social welfare,what must the government do

A) It must disallow synergy benefits from accruing to monopolists.
B) It must disallow any mergers from taking place.
C) It must be able to determine which mergers are desirable and which are not.
D) It must always attempt to keep markets in their most competitive form.