A space expedition discovers a planetary system consisting of a massive star and several spherical planets. The planets all have the same uniform mass density. The orbit of each planet is circular.

In the observed planetary system, Planet A orbits the central star at the distance of 2R and takes T hours to complete one revolution around the star.

Planet B orbits the central star at the distance of R. Which of the following expressions is correct for the number of hours it takes Planet B to complete one revolution around the star?

The correct expression for the number of hours it takes Planet B to complete one revolution around the star is $\frac{1}{\sqrt{8}}.$

$\mathrm{The\; answer\; is\; option\; A.}$

This answer was edited.