Answer:
D
Step-by-step explanation: The vertex is where the curve of the parabola occurs. Pay attention to where the curve of the parabola exists, and write down its coordinates. Over here, the curve is on 3 of the x-axis, and the y-value is 0 because the curve is literally on the x-axis. Any point that is on the x-axis will have no y-value. Hence our answer is (3,0).