The Tensile strength in the rock is given by

A. $$ \in T = \left( {2P} \right)L\left( {\pi dt} \right)$$

B. $$ \in T = \left( {2\pi P} \right)L\left( {d{t^2}} \right)$$

C. $$ \in T = \frac{{2PL}}{{DT}}$$

D. $$ \in T = \frac{{4P}}{{\pi dt}}$$

Answer: Option A