Concept:A number series where each term follows a fixed mathematical rule.Explanation:Check the rule from the second term onwards.6×6−6=3030×6−6=174174×6−6=1038So the pattern is multiply by 6 and subtract 6.If 4 were correct, then 4×6−6=18, not 6.The first term should be 2, because 2×6−6=6.Hence 4 is the wrong term.Answer:4 (Option D)