On heating water, bubbles being formed at the bottom of the vessel detatch and rise. Take the bubbles to be spheres of radius $R$ and making a circular contant fo radius $r$ with the bottom of the vessel. If $r << R$ and the surface tension of water is $T$, value of $r$ just before bubbles detatch is : (density of water is $\rho_w$ )

Question

$\begin{array}{1 1}(A)\;R^2 \sqrt {\large\frac{\rho_wg}{T}} \\ (B)\;R^2 \sqrt {\large\frac{3\rho_wg}{T}} \\(C)\;R^2 \sqrt {\large\frac{\rho_w g}{3T}} \\(D)\;R^2 \sqrt {\large\frac{\rho_w g}{6T}} \end{array} $