Christopher Is 16 and He Is Visiting His Grandfather for the Weekend

Christopher is 16 and he is visiting his grandfather for the weekend. If you could compare EEG recordings from Christopher's sleep and from his grandfather's sleep, which of the following should you expect?

A) Both these individuals will sleep for the same length of time, but Christopher's grandfather will spend substantially less time in REM sleep.
B) Both these individuals will sleep for the same length of time, but Christopher's grandfather will spend substantially more time in REM sleep.
C) His grandfather will sleep less than Christopher, but both will spend about 20 percent of their sleep time in REM sleep.
D) His grandfather will sleep less than Christopher, and also experience proportionately less REM sleep.