The graph of which function has an axis of symmetry at x = 3?

a. f(x) = x2 + 3x + 1

b. f(x) = x2 – 3x – 3

c. f(x) = x2 + 6x + 3

d. f(x) = x2 – 6x – 1

The graph of which function has an axis of symmetry at x = 3?

a. f(x) = x2 + 3x + 1

b. f(x) = x2 – 3x – 3

c. f(x) = x2 + 6x + 3

d. f(x) = x2 – 6x – 1

What is it can you tell me