In a Young's double slit experiment at a point P on the screen the light from two slit with a path difference of $\large\frac{\lambda}{6} $ Where $\lambda$ is the wavelength of the incident light . The intensity of light at point P is I. If $I_0$ is maximum intensity then $\large\frac{I}{I_0}$

Question

$(a)\;\frac{1}{\sqrt 2} \\ (b)\;\frac{\sqrt 3}{2} \\ (c)\;\frac{1}{2} \\ (d)\;\frac{3}{4} $