The stylistic element used in the passage is incongruity. It is a form of satire or humor. Incongruity is used in an unsuitable time. For example, If a man were in a court room and belched loudly while receiving his sentence, that would be a use of incongruity. Another example would be if at a royal wedding the groom's pants fell down in the middle of the ceremony.
The pun is related to the same pronunciation of the words <em>Ernest</em> and <em>earnest </em>which means<em> serious commited, dedicated </em>and etc. The pun is connected to the serious issue of choosing the right significant other, someone you can trust that is dedicated to you (<em>an earnest husband/wife</em>).<em> </em>
I believe the best answer to this question is c
