Answer:
B. x=1
Explanation:
Let us define axis of symmetry first.
The point right in between the two x-intercepts of a quadratic equation is called axis of symmetry.
We have x-intercepts of -3 and 5
In ordered to find the axis of symmetry we have to find their middle intercept
To find the axis of symmetry:

So the axis of symmetry is x = 1 ..