I'm pretty sure the answer is A but I need to show my work and I don't know how to show it

Write a polynomial function in standard form with the given zeros.

x=1, -1, -4

Choose the correct answer below.

a.) f(x) = x^3 +4x^2 - x - 4
b.) f(x) = -4 + x^3 - x + 4x^2
c.) f(x) = 3 + x^3 - x - 4x^2
d.) f(x) = (x-1)(x+1)(x+4)
e.) f(x) = x^3 - 4x^2 - x + 4
f.) f(x) = (x+1)(x-1)(x-4)

Your polynomial will be

y = (x-1)(x+1)(x+4)
= (x^2 - 1)(x+4)
= ......

see which one matches your answer

Just noticed that d) matches my first line