The correct answer is C. Showy.
Ostentatious means characterized by vulgar or pretentious display. It is often used to describe someone who is trying to impress others with their wealth or possessions.
Pretty means pleasing to the eye or mind. It is often used to describe someone or something that is attractive or beautiful.
Modest means having or showing a moderate or humble estimate of one’s own importance or abilities. It is often used to describe someone who is not proud or boastful.
Flagrant means very bad or serious. It is often used to describe something that is illegal or immoral.
In the context of the question, the correct answer is C. Showy. This is because ostentatious is a synonym of showy, which means characterized by vulgar or pretentious display. The other options, pretty, modest, and flagrant, are not synonyms of ostentatious.