The angle of elevation of the summit of a mountain from a point on the ground is \( 45^{\circ} \). After climbing up one…

The angle of elevation of the summit of a mountain from a point on the ground is \( 45^{\circ} \). After climbing up one \( \mathrm{km} \) towards the summit at an inclination of \( 30^{\circ} \) from the ground, the angle of elevation of the summit is found to be \( 60^{\circ} \). Then the height (in km) of the summit from the ground is :

[JEE Main 2020, 6 Sep (Shift 2)]