People know him for his vanity.

Answer: Option D

Vanity : excessive pride in or admiration of one's own appearance or achievements.
Humanity : the quality of being humane; benevolence.
Honesty : the quality of being honest.
Courtesy : the showing of politeness in one's attitude and behaviour towards others.
Modesty : the quality or state of being unassuming in the estimation of one's abilities.

Antonym of Vanity is Modesty