Find a Formula for the Slope of the Tangent Line $y=(x-9)^{2}$

Find a formula for the slope of the tangent line to $y=(x-9) ^{2}$

A) 2x - 18
B) 2x - 9
C) 2(x - 9) ³
D) (x - 9) ³/3
E) none of the above