Applying the principle of homogeneity of dimensions, determine which one is correct, where \( T \) is time period, \( G \) is gravitational constant, \( M \) is mass, \( r \) is radius of orbit.
\( T^2 = 4\pi^2 r^3 \)
\( T^2 = \dfrac{4\pi^2 r}{GM^2} \)
\( T^2 = \dfrac{4\pi^2 r^2}{GM} \)
\( T^2 = \dfrac{4\pi^2 r^3}{GM} \)