A beaker contains a fluid of density $\rho$ kg/m³, specific heat $S$ J/kg°C and viscosity $\eta$. The beaker is filled up to height $h$. To estimate the rate of heat transfer per unit area ($\dot{W}/A$) by convection when beaker is put on a hot plate, a student proposes that it should depend on $\eta$, $(S\Delta\theta/h)$ and $(1/\rho g)$ when $\Delta\theta$ (in °C) is the difference in temperature between the bottom and top of the fluid. In that situation the correct option for ($\dot{W}/A$) is: