Exactly midway between the foot of two towers P and Q, the angles of elevation of their tops are $$45^{\circ}$$ and $$60^{\circ}$$, respectively. The ratio of the heights of P and Q is:

A

1 : $$\sqrt{3}$$

B

3 : 1

C

1 : 3

D

$$\sqrt{3}$$ : 1