One Reason Why Computer-Assisted Instruction Has Great Potential for Training

One reason why computer-assisted instruction has great potential for training is that:

A) fast learners can progress quickly, while slower learners can receive more instruction and more examples.
B) the reliability and validity of test questions is typically much higher than in traditional training assessments.
C) learners are more likely to use effective learning strategies because they design their own training.
D) there is a great deal of research on the subject that indicates it is superior to most other types of training.