First because "AAS" is when we know two angles and one side (which is not between the angles). To solve an AAS triangle. use the three angles add to 180° to find the other angle. then The Law of Sines to find each of the other two sides.
And then C because all angles have to equal to the other angle pattern
He donated 18 books per month. you first finds the difference of the books then do use the number of books by the number of months (in this case it was 5 months)
