HURRY! Hal makes an error when determining the difference quotient of f(x) = x2 + 11x + 2.

His work is shown.
(see picture)

Which statement describes the error?
A. He did not expand (x + h)^2 correctly.
B. He did not combine like terms correctly.
C. He should have subtracted f(x) – f(x + h), not
f(x + h) – f(x).
D. He should have added f(x + h) + f(x), not subtracted
f(x + h) – f(x).