Which form of Kepler’s third law can you use to relate the period T and radius r of a planet in our solar system as long as the unit year is used for the period and astronomical unit is used for the radius?

Responses:

a) T=r^2

b) T^2=r^3

c) T^2=r

d) T^3=r^2

b) T^2=r^3

The correct form of Kepler's third law that relates the period T and radius r of a planet in our solar system, when the unit year is used for the period and astronomical unit is used for the radius, is:

Option (b) T^2 = r^3