Self-testing crushes re-reading on long-delay retention

Correct: C — Larger gains in long-term retention, with benefits that grow as the retention interval lengthens

Roediger & Butler (2011) synthesized over a century of research showing that the act of retrieval — practicing answering questions, generating, or self-testing — yields more durable long-term retention than equivalent time spent re-reading. The advantage typically appears small or absent on immediate tests but grows with delay; at delays of a week or longer, retrieval practice can yield substantially higher recall than restudy. The mechanism likely involves both elaborative semantic re-encoding and recruitment of overlapping retrieval cues. The finding underwrites spaced-retrieval study schedules and 'low-stakes quizzing' classroom recommendations.