Point P is inside equilateral \triangle A B C. Points Q, R, and S are the feet of the perpendiculars from P to \overline{A B}, \overline{B C}, and \overline{C A}, respectively. Given that P Q=1, P R=2, and P S=3, what is A B ?
Answer Choices
A. 4
B. 3 \sqrt{3}
C. 6
D. 4 \sqrt{3}
E. 9