If the angles of elevation of a balloon from two consecutive kilometre-stones along a straight road are 30° and 60° respectively, then the height of the balloon above the ground will be (assume the balloon is in the between the two mile stones)

• A. \(√3/2\) km
• B. \(4/√3\) km
• C. \(2√3\) km
• D. \(3√3\) km