The correct answer is: A. humanity.
Vanity is excessive pride in one’s own appearance, abilities, or achievements. It is often associated with arrogance, conceit, and egotism.
Humanity is the quality of being humane, or showing kindness and compassion to others. It is often associated with empathy, sympathy, and altruism.
Honesty is the quality of being truthful and fair. It is often associated with integrity, trustworthiness, and reliability.
Courtesy is the quality of being polite and considerate. It is often associated with manners, etiquette, and respect.
Modesty is the quality of being humble and unassuming. It is often associated with shyness, reserve, and discretion.
In the context of the question, “People know him for his vanity,” the most likely answer is that he is known for his excessive pride in his own appearance, abilities, or achievements. This is because vanity is a trait that is often associated with arrogance, conceit, and egotism.
The other options are less likely because they do not describe the person in the question as being known for his excessive pride in his own appearance, abilities, or achievements. For example, the person is not known for his kindness and compassion to others (humanity), his truthfulness and fairness (honesty), his politeness and consideration (courtesy), or his humility and unassuming nature (modesty).