If $$\Box$$ and $$\rightarrow$$ are defined by $$a \Box b = \frac{a - b}{a + b}$$ and $$a \rightarrow b = ab$$ then $$\frac{(66 \Box 6) \rightarrow 66}{55 \Box 5} =$$

A

60

B

66

C

50

D

55