Expression of time in terms of G (universal gravitational constant), h (Planck’s constant) and c (speed of light) is proportional to

$\begin{array}{l}\mathrm{F}=\frac{{\mathrm{GM}}^2}{{\mathrm{R}}^2}\Rightarrow \mathrm{G}=\left[{\mathrm{M}}^{-1}{\mathrm{L}}^3{\mathrm{T}}^{-2}\right]\\ \mathrm{E}=\mathrm{hv}\Rightarrow \mathrm{h}=\left[{\mathrm{ML}}^2{\mathrm{T}}^{-1}\right]\\ \mathrm{C}=\left[{\mathrm{LT}}^{-1}\right]\\ \begin{array}{l}t\propto G^x{h}^y{C}^z\\ \left[T\right]={\left[M^{-1}{L}^3{T}^{-2}\right]}^x{\left[M{L}^2{T}^{-1}\right]}^y{\left[L^{-1}\right]}^z\\ \left[M^0{L}^0{T}^1\right]=\left[M^{-x+y}{L}^{3x+2y+z}{T}^{-2x-y-z}\right]\\ on comparing the powers of M, L, T\end{array}\\ -x+y=0\Rightarrow x=y\\ 3x+2y+z=0\Rightarrow 5x+z=0\\ \mathrm{x}=\mathrm{y}=\frac{1}{2},\mathrm{z}=-\frac{5}{2}\\ t\propto \sqrt{\frac{\mathrm{Gh}}{{\mathrm{C}}^5}}\\ \end{array}$