Wilson cuts rectangular mats for picture frames. The area of the mat before it is cut is represented by the function M(x) = 4.5x2 + 17x + 16. The area that is cut out and removed from the middle of the mat is represented by the function N(x) = x2 + 6x. If x is the width of the portion of the mat that is cut out, which function best describes A(x), the area of the cut mat?
A.
A(x) = 3.5x2 + 11x + 16

B.
A(x) = 5.5x2 + 23x + 16

C.
A(x) = 4.4x2 + 17x + 10

D.
A(x) = 4.5x2 + 16x + 10