A ladder whose length is 10 m lies on a wall at a height of 5 m. What could be the angle of inclination in radian measure ?

Question

$\begin{array}{1 1} (a)\;\large\frac{\pi}{3} \\ (b)\;\large\frac{\pi}{6}\\ (c)\;\large\frac{\pi}{4} \\ (d)\;\large\frac{\pi}{8} \end{array} $