Sam Sleeps for Eight or More Hours Every Night but Never

Sam sleeps for eight or more hours every night but never feels rested.He can't understand why he is always tired despite the fact that he reports no difficulties with the quality or quantity of his sleep.Of the following, Sam's most likely diagnosis is

A) hypersomnolence disorder.
B) sleep apnoea.
C) narcolepsy.
D) non-specific parasomnia.