The graphs of y=\log _{3} x, y=\log _{x} 3, y=\log _{\dfrac{1}{3}} x, and y=\log _{x} \dfrac{1}{3} are plotted on the same set of axes. How many points in the plane with positive x-coordinates lie on two or more of the graphs?
Answer Choices
A. 2
B. 3
C. 4
D. 5
E. 6