An ordinary light of intensity $I_0$ is passed through a polarised $P_1$ which is crossed with another polaroid $P_2$. Now a third polaroid is placed in between $P_1$ and $P_2$ with its pass axis making an angle $\beta$ with the pass axis of $P_1$. The value of $\beta$ for which the intensity of light from $P_2$ is $\frac{I_0}{8}$ is:

45°

The correct answer is Option (4) → 45°