what is the answer please? show step by step

Answer:
D
Step-by-step explanation:
f(x-3) = (x-3)^2 - 8
f(x-3) = (x-3)(x-3) - 8
f(x-3) = x^2 - 6x + 9 - 8
f(x-3) = x^2 - 6x + 1