If $$a ⊙ b = \sqrt{ab} + \frac{1}{\sqrt{ab}}$$ and $$a \triangle b = \sqrt{ab} - \frac{1}{\sqrt{ab}}$$, then $$\frac{4 ⊙ 9 + 4 \triangle 9}{4 ⊙ 9 - 4 \triangle 9} =$$

A

$$\frac{1}{36}$$

B

$$\frac{1}{18}$$

C

$$18$$

D

$$36$$