The angle of elevation of a stationary cloud from a point 2500 m above a lake is $15^{\circ}$ and from the same point the angle of depressed its reflection in the lake is $45^{\circ}$. The height (in meters) of the cloud above the lake , given that $\cot 15^{\circ}=2+\sqrt {3}$, is

Question

$$\begin {array} {1 1} (a)\;2500 & \quad (b)\;2500 \sqrt 2 \\ (c)\; 2500 \sqrt 3 & \quad (d)\;5000 \end {array}$$