...(8) Although babies can do little more than eat, sleep, and cry, their brains are incredibly busy building neural pathways, processing new information, and developing language. (9) In fact, a recent study shows that newborns are even capable of learning in their sleep...

The writer wants to add a sentence before sentence 8 to show that the third paragraph is refuting the claim made in the second paragraph. Which sentence best accomplishes the writer’s goal?

a.) Not only do babies’ eyes move side to side during REM sleep, but they also move up and down.
b.) However, child psychologist David Foulkes argues that babies use REM sleep for other purposes.
c.) Contrary to popular belief, REM accounts for only one of the five stages of sleep that all humans, including infants, go through.
d.) On the other hand, one study conducted in 2010 indicated that babies have the ability to learn while they are sleeping.
e.) Whereas adults spend only a quarter of their sleep time in the REM stage, babies average closer to half their sleep time in this stage.