A ladder is placed against a wall such that it just reaches the top of the wall. The foot of the ladder is at a distance of 5 metres from the wall. The angle of elevation of the top of the wall from the base of the ladder is 15°. What is the length (in metres) of the ladder?

• A. 5√6 - 5√3
• B. 5√6 - 5√2
• C. 5√2 - 1
• D. 5√3 + 5√2