Which function in vertex form is equivalent to f(x) = 4 + x2 – 2x?

(a) f(x) = (x – 1)2 + 3
(b )f(x) = (x – 1)2 + 5
(c) f(x) = (x + 1)2 + 3
(d) f(x) = (x + 1)2 + 5