Answer:
She believes in adherence to societal expectations.
Step-by-step explanation:
Oscar Wilde's comedy play "The Importance of Being Ernest" revolves around the story of two men, Algernon "Algy" Moncrieff and John "Jack" Worthing. The play follows the men through their desire to enjoy some excitement in their lives, for which they made up names and identities to be able to enjoy some 'downtime'.
In the given excerpt of the play, the character of Miss Prism is revealed to be the one who placed Jack in the bag. But when jack revealed the truth and called her "mother", Miss Prism "recoil[ed] in indignant astonishment". This reaction seems to suggest that she believes in strict adherence to society's expectations, especially of women. That was why she did not really acceptable to be called "mother" as she's still "unmarried."
Thus, the correct answer is the third option.