(Corrects euro rate in paragraph 9) By Hannah Lang and Amanda Cooper WASHINGTON/LONDON (Reuters) -The yen staged its biggest one-day rally in almost a year on Thursday after Japanese monetary authorities offered a surprisingly clear hint at a shift in policy, while the euro headed for its biggest weekly fall since May. The dollar index eased ahead of Friday’s U.S. non-farm payrolls report, under pressure mostly from the yen, which rose by nearly 2% to its strongest in three months. Bank of Japan (BOJ) Governor Kazuo Ueda said on Thursday the central bank has several options on which interest r…