Question

the inability to sleep, even if an individual is tired, is called what?
insomnia
lack of sleep
exhaustion

Explanation:

Insomnia is defined as the inability to fall asleep or stay asleep, even when one is tired. "Lack of sleep" is a general term for not getting enough sleep, and "Exhaustion" refers to extreme tiredness, not the inability to sleep. So the correct term for the described condition is Insomnia.

Answer:

A. Insomnia