In One Study,8 Volunteers Reduced Their Sleep by 30 Minutes

In one study,8 volunteers reduced their sleep by 30 minutes per night until they did not want to reduce it further.A major finding was that

A) 4 managed to reduce their sleep to 5 hours per night.
B) 2 managed to reduce their sleep to 4.5 hours per night.
C) the volunteers began to experience significant daytime sleepiness once they had reduced their sleep to 6 hours or less per night.
D) the volunteers were still sleeping between 7 and 18 hours less per week when they were tested 1 year after the experiment ended.
E) all of the above