Open this photo in gallery:U.S. Trade Representative Jamieson Greer departs following a Senate Finance Committee hearing on Wednesday in Washington.Andrew Harnik/Getty ImagesSave for laterThe United States’ top trade official said he’s aiming to negotiate interim deals with Canada and Mexico by the end of the year, while discussions about more fundamental changes to continental trade rules are expected to stretch into the new year.In a Senate committee hearing on Wednesday, U.S. Trade Representative Jamieson Greer said he was hoping to present “options” for “potential interim arrangements” to President Donald Trump, Mexican President Claudia Sheinbaum and Prime Minister Mark Carney before…