BERLIN (Reuters) - The leader of the Germany s Social Democrats (SPD) said nothing had been ruled out ahead of talks with Chancellor Angela Merkel s conservatives on forming a new government, but added that there was no certainty of success.  No options are off the table,  SPD leader Martin Schulz told a news conference at his party s Berlin headquarters on Monday, adding that it was impossible to say where preliminary talks, due to begin on Thursday, would lead. 