If the height of the hydraulic gradient line above the floor of thickness t is h and the specific gravity of the material of the floor is G, the minimum thickness t of the floor downstream of the crest-wall, is given by the equation

A. $${\text{t}} = \frac{{{\text{h}} + 1}}{{{\text{G}} + {\text{t}}}}$$

B. $${\text{t}} = \frac{{{\text{h}} - 1}}{{{\text{G}} + {\text{t}}}}$$

C. $${\text{t}} = \frac{{{\text{h}} - 1}}{{{\text{G}} - {\text{t}}}}$$

D. $${\text{t}} = \frac{{{\text{h}} + 1}}{{\text{G}}}$$

Answer: Option C