Oil prices fell on Monday, with U.S. crude falling close to a nearly six-year low, as Saudi Arabia’s new King Salman moved to assuage fears of an unstable transition and any policy change in the world’s largest oil exporter. Salman was quick to retain veteran Saudi oil minister Ali al-Naimi on Friday, in a message aimed at calming a jittery energy market following the death of King Abdullah last week. West Texas Intermediate (WTI) crude for March delivery (CLc1) was at $45.10 a barrel, down 49 cents.