Let A and B be two towers with same base. From the midpoint of the line joining their feet. the angles of elevation of the tops of A and B are $$30^\circ$$ and $$60^\circ$$, respectively. The ratio of the heights of B and A is:

A

$$1 : 3$$

B

$$3 : 1$$

C

$$1 : 2$$

D

$$1 : \sqrt{3}$$