Uhhh.. help, please..

Given a circle with a radius of 3, which equation expresses π as the ratio of the circumference of a circle to its diameter?
A)
[tex]\frac{C}{3}[/tex]= π
B)
[tex]\frac{C}{6}[/tex]= π
C)
[tex]\frac{3}{C}[/tex]= π
D)
[tex]\frac{6}{C}[/tex]= π