A parabola with equation y=a x^{2}+b x+c is reflected about the x-axis. The parabola and its reflection are translated horizontally five units in opposite directions to become the graphs of y=f(x) and y=g(x), respectively. Which of the following describes the graph of y=(f+g)(x) ?
Answer Choices
A. a parabola tangent to the x-axis
B. a parabola not tangent to the x-axis
C. a horizontal line
D. a non-horizontal line
E. the graph of a cubic function