WASHINGTON (Reuters) - U.S. Senate Democratic leader Chuck Schumer said on Monday his party would look at “every single option” to halt a last-ditch effort by Republicans to repeal and replace former President Barack Obama’s signature healthcare law. “We’re going to explore every single option,” Schumer told a news conference to underscore Democratic opposition to a bill introduced by Republican Senators Lindsey Graham and Bill Cassidy that proposes replacing the 2010 Affordable Care Act. Republicans face a two-week countdown before Senate procedural rules make it much harder for them to advance their latest bill. 