A cube subjected to three mutually perpendicular stress of equal intensity p expenses a volumetric strain

A. $$\frac{{3{\text{p}}}}{{\text{E}}} \times \frac{2}{{{\text{m}} - 1}}$$

B. $$\frac{{3{\text{p}}}}{{\text{E}}} \times \left( {2 - {\text{m}}} \right)$$

C. $$\frac{{3{\text{p}}}}{{\text{E}}} \times \left( {1 - \frac{2}{{\text{m}}}} \right)$$

D. $$\frac{{\text{E}}}{{3{\text{p}}}} \times \frac{2}{{{\text{m}} - 1}}$$

Answer: Option C