Aniya is solving the equation 9n+7=-56. One of her steps is to divide both sides of the equation by 9. Why?
A. Dividing both sides by 9 undoes the multiplication of n by 9 in the original problem.
B. Dividing both sides by 9 undoes the subtraction in the original problem.
C. Dividing both sides by 9 undoes the addition in the original problem.
D. The negative sign in -56 must be changed to positive.