In this text, we learn that Beth wants to convince one of her sisters to go visit the Hummels. She has visited constantly but wants someone else to go as well. However, we learn that her other sisters are not as dutiful, as they seem very reluctant to carry out this visit, even after promising they would do it.
Sally Lockhart is a dazzling 16-year-old; middle-class orphan whose father taught her a variety of useful things; accounting, marksmanship, finance and shooting.
A. It is indeed a pun. The writer's purpose of this may have been to teasingly warn a character. You can easily cancel out the other answer options as well.