Answer:
B: However, child psychologist David Foulkes argues that babies use REM sleep for other purposes.
Explanation:
From College Board: In the second paragraph, the claim is that because babies spend so much of their time in REM sleep, the stage at which dreaming occurs for adults, they most likely experience dreams. The third paragraph refutes that claim, starting with this sentence that references an expert in the field who argues that babies use their REM sleep time for “other purposes.”
