Family Dollar Stores, Inc. (NYSE:FDO) has rejected the $9 billion buyout offer from Dollar General Corp. (NYSE:DG), citing concerns that the merger of the nation’s two largest discount retailers might not pass anti-trust review, sending both stock slightly down in trading today. “Our board reviewed, with our advisers, all aspects of Dollar General’s proposal and unanimously concluded that it is not reasonably likely to be completed on the terms proposed,” said Family Dollar CEO Howard Levine, report Matt Townsend and David Welch for Bloomberg. Discount retail CEOs are talking past each other Dollar General Corp. (NYSE:DG) CEO Rick Dreiling has…