Answer:
Option D) x = 0
Explanation:
Axis of symmetry is a line that divides an object into two equal halves, thereby creating a mirror-like reflection of either side of the object. Here we see that the object's Axis of symmetry is the line x =0
The line x = 0,1,2,3,4,5,..... and so on are all vertical lines and
The line y=0,1,2,3,4,5,..... and so on are all horizontal lines
In this this case the line x = 0 is the Axis of symmetry which divides the object in two equal halves.