Final answer:
Vanity best matches the word 'egotism' as it refers to an excessive focus on one's own qualities, contrasting with humility, selflessness, and modesty.
Step-by-step explanation:
The word "vanity" closely matches the word "egotism" (option a). Vanity refers to excessive pride in or admiration of one's own appearance or achievements. It is characterized by a focus on oneself and one's own qualities, often disregarding others.
This is in direct contrast to humility, selflessness, and modesty, which all involve a lower estimation of one's own importance or a focus on others. Therefore, the best match for "vanity" from the given options is egotism.