Which Statement Is TRUE Regarding REM Sleep

Which statement is TRUE regarding REM sleep?

A) Some studies have shown that REM-deprived people have improved concentration.
B) There is a possible link between REM sleep and memory processing.
C) REM sleep tends to clutter the brain with trivial or unimportant information.
D) REM deprived people are twice as likely to have a mental health problem as non-REM deprived people.