What is the normal stress on a bar of square cross- section with side ‘b’ on which load P is applied at an angle of 30o from the horizontal?

A

$$\frac{\sqrt{3P}}{2b^2}$$

B

$$\frac{\sqrt{3P}}{4b^2}$$

C

$$\frac{\sqrt{3}P}{2b^2}$$

D

$$\frac{\sqrt{3}P}{4b^2}$$