I read the book so you can ask your questions.
To get the answer u must do (-7273828)+(28272838)-(2728283)=(-268473847)
Alexandra claims that both she and Atticus decided it was time for Scout to have a feminine influence.
B is the most realistic answer considering Amerigo's objective: to provide the students with one-on-one Italian instruction. The rest of them are not one-on-one and are pretty unnecessary.
I hope I helped!
