A baloon is moving up in air vertically above a point A on the ground. When it is at a height , a girl standing at a distanced (point ) from (see figure) sees it at an angle with respect to the vertical. When the balloon climbs up a further height , it is seen at an angle with respect to the vertical if the gitl moves further by a distance (point ). Then the height is (given ) :
Option: 1
Option: 2
Option: 3
Option: 4