Which of the following may explain the testing effect noted by Roediger and others?

A) Testing requires cognitive effort to be exerted on information.
B) Testing may reveal what information is not easily remembered.
C) Repeated testing may create retrieval cues for later retrieval.
D) all of these

The testing effect, as noted by Roediger and others, is explained by all the provided options: A) Testing requires cognitive effort, which helps in encoding information more deeply. B) Testing reveals what information is not easily remembered, allowing for targeted studying. C) Repeated testing creates retrieval cues, enhancing the ability to recall information later.