The correct answer is B. pretence.
Affection is a false or exaggerated display of emotion or behavior. It can be used to deceive or manipulate others, or to make oneself appear more important or interesting than one really is.
Boasting is the act of talking about one’s own achievements or possessions in a way that is considered to be boastful or arrogant.
Pedantry is excessive concern with minor details or rules.
Euphemism is a word or phrase that is used to replace a more direct or unpleasant word or phrase.
In the context of the question, the speaker is using affectation to make himself appear more important or interesting than he really is. He is not being boastful, pedantic, or using euphemisms.