A man observes the angle of elevation of the top of mountain to be 30°. He walks 1000 feet nearer and finds the angle of elevation to be 45°. What is the distance of the first point of observation from the foot of the mountain?

• A. \(\rm 500\sqrt{3}(\sqrt{3}+1)ft\)
• B. \(\rm 500(\sqrt{3}+1)ft\)
• C. \(\rm 500(\sqrt{3}-1)ft\)
• D. \(\rm 500\sqrt{3}(\sqrt{3}-1)ft\)