A self-possessed person is one who is very assured of his or her own capabilities, is quite calm and collected, and just generally cool.
Having this in mind, the way that the character of the niece can be described is B. confident.
The other options don't make much sense here.
4. by? I know for sure it not 1. for and 3. from.
Our team has won more games than has any other team. - Sounds more illogical
The answer is A: She no longer has as many responsibilities as she once did
