A man standing at a point P is watching the top of a tower, which makes an angle of elevation of 30° with the man's eye. The man walks some distance towards the tower to watch its top and the angle of the elevation becomes 60°. What is the distance between the base of the tower and the point P?

• A. 43 units
• B. 8 units
• C. 12 units
• D. Data inadequate
• E. None of these