Answer:
C. y = [x] - 6
Explanation:
The point that lies on the x-axis is sitting at (6,0), 6 being x and 0 being y, when you relpace the [x] with 6 and do the equation, you will get 0, which is what y happens to be equal to.
x = 6
y = [6] - 6 = 0
y = 0