How would you describe someone who is "unconscious"?

The description that best characterizes someone who is "unconscious" is one that conveys the state of being not awake or aware, particularly as it may relate to a medical condition or trauma, such as a head injury. When a person is in an unconscious state, they do not have awareness of their environment and cannot respond to external stimuli. This definition accurately encompasses both the absence of wakefulness and the potential causes, making it the most comprehensive and accurate choice.

The other options do not accurately convey the medical context surrounding unconsciousness. For example, simply being "always asleep" suggests a normal sleep cycle rather than a medical condition. Describing someone as "not physically active" overlooks the critical aspect of mental awareness. Finally, being "not mentally awake" is quite vague and does not capture the seriousness of the condition, especially in situations caused by injury.