Concept:The series follows a pattern of differences that decrease by 1 each time.Explanation:Find the differences between consecutive terms:43−30=1330−16=1416−1=15So the next difference should be 16.Then the next term should be 1−16=−15.But the given term is 18, which does not match.Therefore, 18 is the wrong number in the series.Answer:The wrong number is 18, which is option B.