The correct option is B Relieved
The poem "When I am an Old Lady" conveys to the reader, in humorous manner, the trials and tribulations of being a parent. She does this by listing all the ways she will 'get back' at her kids when she's old. In this context, the line, "And say with a groan, "She's so sweet when she's sleeping", reflects the relief that her children would feel when she would no longer be awake to get into mischief. Option B is the best answer.