Answer:
a) Insomnia
Step-by-step explanation:
Among all the numerous sleep-wake disorder insomnia is the most prevalent.
Insomnia can be refferered to as the persistent problem associated with an individual's ability or inability to fall asleep and stay sleeping. And not feeling as though you have rested well.
It is always self diagnosed as in most cases doesn't require any clinical examination to determine ones state.
It can be treated by basic self care most especially by improving sleep habit.