If the eccentricity of a hyperbola is $\sqrt 3$; then the eccentricity of its conjugate hyperbola is :

Question

$$\begin {array} {1 1} (a)\;\sqrt 2 & \quad (b)\;\sqrt 3 \\ (c)\;\sqrt {\frac{3}{2}} & \quad (d)\;2 \sqrt 3 \end {array}$$