$$AB$$ is a vertical pole with $$B$$ at the ground level and $$A$$ at the top. A man finds that the angle of elevation of the point $$A$$ from a certain point $$C$$ on the ground is $$60^\circ$$. He moves away from the pole along the line $$BC$$ to a point $$D$$ such that $$CD = 7$$ m. From $$D$$ the angle of elevation of the point $$A$$ is $$45^\circ$$. Then the height of the pole is

A

$$\frac{7\sqrt{3}}{2} \cdot \frac{1}{\sqrt{3} - 1}\ m$$

B

$$\frac{7\sqrt{3}}{2} \cdot (\sqrt{3} + 1)\ m$$

C

$$\frac{7\sqrt{3}}{2} \cdot (\sqrt{3} - 1)\ m$$

D

$$\frac{7\sqrt{3}}{2} \cdot \frac{1}{\sqrt{3} + 1}\ m$$