Let $$f: R \to R$$ be a positive increasing function with $$\lim_{x \to \infty} \frac{f(3x)}{f(x)} = 1$$. Then $$\lim_{x \to \infty} \frac{f(2x)}{f(x)} =$$

A

$$\frac{2}{3}$$

B

$$\frac{3}{2}$$

C

3

D

1