Concept:Insects grow by metamorphosis, which may be complete or incomplete based on their life stages.Explanation:Incomplete metamorphosis involves only three stages:egg→nymph→adultComplete metamorphosis involves four stages:egg→larva→pupa→adultThe locust, grasshopper, and cockroach all hatch as nymphs that look like small adults and slowly develop wings. Therefore, they undergo incomplete metamorphosis.The butterfly has a caterpillar larval stage and a chrysalis pupal stage. Therefore, it undergoes complete metamorphosis, not incomplete metamorphosis.Answer:C. butterfly