When a body is subjected to a direct tensile stress $$\left( {{\sigma _{\text{x}}}} \right)$$  in one plane accompanied by a simple shear stress $$\left( {{\tau _{{\text{xy}}}}} \right),$$  the maximum normal stress is

A. $$\frac{{{\sigma _{\text{x}}}}}{2} + \frac{1}{2} \times \sqrt {\sigma _{\text{x}}^2 + 4\tau _{{\text{xy}}}^2} $$

B. $$\frac{{{\sigma _{\text{x}}}}}{2} - \frac{1}{2} \times \sqrt {\sigma _{\text{x}}^2 + 4\tau _{{\text{xy}}}^2} $$

C. $$\frac{{{\sigma _{\text{x}}}}}{2} + \frac{1}{2} \times \sqrt {\sigma _{\text{x}}^2 - 4\tau _{{\text{xy}}}^2} $$

D. $$\frac{1}{2} \times \sqrt {\sigma _{\text{x}}^2 + 4\tau _{{\text{xy}}}^2} $$

Answer: Option A