A spherical liquid drop is placed on a horizontal plane. A small distance causes the volume of the drop to oscillate. The time period of oscillation (T) of the liquid drop depends on radius (r) of the drop, density ($$\rho $$) and surface tension (S) of th liquid. Which among the following will be a possible expression for T (where, k is a dimensionless constant)?

The dimension of the universal constant of gravitation, G is

If x = at + bt², where x is in metre (m) and t is in hour (h), then unit of b will be