An astronaut tries to drop an object from a height of 10 m on the surface of the moon. How long will it take to reach the moon's surface? [take g= $10m/s^2$]

Question

$\begin{array}{1 1} (a)\ \sqrt{10}s \\ (b)\; \sqrt{12}s \\ (c)\; \sqrt{15}s \\ (d)\; \sqrt{18}s \end{array}$