What are common signs of sleep deprivation?

The choice pertaining to fatigue and cognitive impairment accurately reflects the common signs of sleep deprivation. When a person experiences inadequate sleep, it can lead to significant physical and mental exhaustion, which is often characterized by overwhelming fatigue. This lack of rest can also severely hamper cognitive functions, resulting in difficulties with concentration, decision-making, problem-solving, and memory retention.

In contrast, the other options describe outcomes that are typically not associated with sleep deprivation. For instance, increased energy and focus would imply a well-rested state rather than the fatigue resulting from insufficient sleep. Enhanced mood stability is also unlikely; in fact, sleep deprivation can lead to irritability and heightened emotional responses. Lastly, improved performance is generally linked with adequate sleep, as rest is crucial for optimal functioning in both physical and mental tasks. Thus, the signs of sleep deprivation align closely with the symptoms of extreme tiredness and diminished cognitive ability, making the chosen answer the most accurate reflection of the effects of inadequate sleep.