The function f(x)=(x-9)² + 3 is not one-to-one. Restrict the function's domain and find its inverse.

A. restricted domain: x29; f⁻¹(x) = √x-9+3
B. restricted domain: x ≤ 9; f⁻¹(x) = √x-3+9
C. restricted domain: x29; f⁻¹(x) = √x-3+9
D. restricted domain: x 23; f⁻¹(x) = √x-3+9