How do the interpretations of facts presented by the authors differ from each other?

A.
The first author uses a study to support brain-training games to make people more intelligent. However the second author uses a study to show that intelligence stayed the same after brain-training games.

B.
The first author believes that brain training programs make people smarter. However the second author believes that brain-training programs are harmful.

C.
The first author wants people to achieve their health goals. However, the second author wants people to improve their performance on specific tasks.

D.
The first author argues online games are needed to improve memory. However the second author argues that any games will work to improve memory.