Imagine a light planet revolving around a very massive star in a circular orbit of radius \( r \) with a period of revolution \( T \). If the gravitational force of attraction between the planet and the star is proportional to \( r^{-5/2} \), then the square of the time period will be proportional to.
1
\( r^3 \)
2
\( r^2 \)
3
\( r^{2.5} \)
4
\( r^{3.5} \)