The sentence D'après lui, l'habit ne fait pas le... ("According to him, the clothes do not make the...") is an incomplete French proverb. The full proverb is:
L'habit ne fait pas le moine.
This literally translates to "The habit (clothing) does not make the monk." It means that one should not judge a person's character or abilities by their outward appearance. It is the French equivalent of the English proverb "Don't judge a book by its cover."
The word moine (monk) completes the proverb. A monk's habit (robe) is distinctive, but wearing one does not actually make a person a monk - hence the proverb's lesson about appearances being deceptive.
The other options do not complete any known French proverb: style (style), prêtre (priest), and riche (rich person) are not part of this expression. While prêtre is semantically related to religious life, the established proverb specifically uses moine.
