Two planets A and B of equal mass are having their period of revolutions ${\mathrm{T}}_{\mathrm{A}}$ and ${\mathrm{T}}_{\mathrm{B}}$ such that ${\mathrm{T}}_{\mathrm{A}}=2{\mathrm{T}}_{\mathrm{B}}$. These planets are revolving in the circular orbits of radii ${\mathrm{r}}_{\mathrm{A}}$ and ${\mathrm{r}}_{\mathrm{B}}$ respectively. Which out of the following would be the correct relationship of their orbits?