One of the most vexing problems in historiography is dating an event when the usual sources offer conflicting chronologies of the event. Historians should attempt to minimize the number of competing sources, perhaps by eliminating the less credible ones. Once this is achieved and several sources are left, as often happens, historians may try, though on occasion unsuccessfully, to determine independently of the usual sources which date is more likely to be right. Which one of the following inferences is most strongly supported by the information above? ['Attaching a reliable date to any event requires determining which of several conflicting chronologies is most likely to be true.', 'The soundest approach to dating an event for which the usual sources give conflicting chronologies is to undermine the credibility of as many of these sources as possible.', 'Some of the events for which there are conflicting chronologies and for which attempts have been made by historians to determine the right date cannot be dated reliably by historians.', 'We have no plausible chronology of most of the events for which attempts have been made by historians to determine the right date.']