Let the Orbital Radius of a Planet Be R and Let

Multiple Choice

Let the orbital radius of a planet be R and let the orbital period of the planet be T. What quantity is constant for all planets orbiting the sun, assuming circular orbits?

A) $T ^ { 2 } / R 3$
B) $T ^ { 2 } / R$
C) $T / R 2$
D) $T ^ { 3 } / R ^ { 2 }$
E) T/R