Concept:The series follows a pattern where the gap between consecutive terms increases by 2.Explanation:If the correct sequence is 49,51,55,61,69, then the differences are:51−49=255−51=461−55=669−61=8So the required pattern is +2,+4,+6,+8.The term 54 breaks this pattern; it should be 51.Therefore, 54 is the odd one out.Answer:The odd number is 54, which is option E.