How does the author's characterization of bertha can reveal delia's attitude towards sykes' affair?

This short story is called “Sweat”, written by Zora Neale Hurston.  

Question: How does the author's characterization of Bertha help reveal Delia's attitude toward Sykes' affairs?

C. By describing only Bertha's negative characteristics, the author hints at Delia's confidence in her own desirability as a wife.

Delia had for some time already been fed up with her no-good husband and she knew that she was the breadwinner in the home,  so in fact she did not need him to live happily ever after. Therefore,  she was confident in her own desirability as a wife.  

being untruthful

eating too much

overstaying one's welcom

this is that correct answer.