Op-Ed: Exxon Mobil Corp. shareholders voted yesterday  to keep the world's largest oil company focused on fossil fuels. Some institutional investors and individual stock holders raised strong objections, saying that Exxon's focus on R&D is not enough for a company if its size and scope. A proposal for reducing Exxon's greenhouse gas targets also failed in a landslide vote of opposition. "We're in the business of oil and gas," CEO Rex Tillerson said, responding to the protests. Meanwhile, all Exxon directors were re-elected with more than 90 percent of votes cast.