Key PointsAt this point, it's mulling over different options and might not opt for a full ban.Marathon is a major producer of diesel in this country.10 stocks we like better than Marathon Petroleum › The latest White House proposal to rein in diesel prices and an analyst's recommendation downgrade were the major factors behind Marathon Petroleum's (NYSE: MPC) stock price dip on Tuesday. At the close of that day's trading session, the company's e…