If the roots ofax^2 + bx + c = 0 are real, rational, and equal, what is true about the graph of the function
y = ax^2 + bx + c?
(1) It intersects the x-axis in two distinct points.
(2) It lies entirely below the x-axis.
(3) It lies entirely above the x-axis.
(4) It is tangent to the x-axis.