By Julien Pretot PRA LOUP, France (Reuters) - With only three competitive stages left in the Tour de France, Chris Froome believes his rivals are going to take an all-or-nothing approach to the race. The Briton retained the overall leader's yellow jersey after holding off his main rival, Colombian Nairo Quintana, on Wednesday's 17th stage, while Alberto Contador lost a big chunk of time and Tejay van Garderen abandoned the race. Making up that much time by attacking in the final climbs is highly unlikely to unsettle Froome, who might be thrown off balance if his rivals take their chance earlier in the stage. More...