Convection

A beaker contains a fluid of density ρ kg/m$^3$, specific heat S J/kg°C and viscosity η. The beaker is filled up to height h. To estimate the rate of heat transfer per unit area $(\dot Q/A)$ by convection when beaker is put on a hot plate, a student proposes that it should depend on η, $\left(\dfrac{S\Delta\theta}h\right)$ and $\left(\dfrac1{\rho g}\right)$ when Δθ (in °C) is the difference in the temperature between the bottom and top of the fluid. In that situation the correct option for $(\dot Q/A)$ is :