Concept:Forgetfulness can be reduced by using effective learning strategies. One key method is repeatedly reviewing the material.Explanation:Repetition strengthens memory traces in the brain. When you go over a lesson multiple times, you create stronger neural connections. This makes recall easier and prevents forgetting. Options like underlearning, defective method, or less attention all increase forgetfulness, not minimize it. Therefore, among the given choices, repetition is the correct way to minimize forgetfulness.Answer:C. Repetition of lesson