Which symptoms are indicative of a fatigued person's appearance?

B is the most suitable choice because it highlights common signs of fatigue that are observable in a person's demeanor. When an individual is fatigued, they often exhibit sleepiness and may frequently yawn as their body signals the need for rest. Additionally, irritability is a common emotional response to fatigue, which can stem from both physical exhaustion and mental stress.

In contrast, heightened energy and alertness would suggest that the person is not fatigued, as fatigue typically results in decreased energy levels. Increased enthusiasm and social interaction are indicators of a person feeling well-rested and engaged, rather than worn out. Similarly, enhanced concentration and performance are traits associated with alertness and vitality, not fatigue. Thus, the symptoms of sleepiness, yawning, and irritability accurately reflect the appearance of someone who is experiencing fatigue.