Which of the following lines is tangent to the parabola y2=8xy^2 = 8xy2=8x?
y=x+2y = x + 2y=x+2
y=2x+1y = 2x + 1y=2x+1
y=x−1y = x - 1y=x−1
y=0.5x+4y = 0.5x + 4y=0.5x+4