HURRY Moira uses a difference quotient to determine the average rate of change of f(x) = x^2 + 14x from x = –11 to x = 8.

She shows the following work.
(see picture)

Which statement summarizes Moira’s work?
A. She correctly found the average rate of change.
B. She expanded the expression for f(x + h) incorrectly.
C. She simplified the difference quotient incorrectly. f(x+h) - f(x) / h
D. She substituted incorrectly when evaluating the difference quotient.