Two nonhorizontal, non vertical lines in the x y-coordinate plane intersect to form a 45^{\circ} angle. One line has slope equal to 6 times the slope of the other line. What is the greatest possible value of the product of the slopes of the two lines?
Answer Choices
A. \dfrac{1}{6}
B. \dfrac{2}{3}
C. \dfrac{3}{2}
D. 3
E. 6