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

Question

( A ) $1$
( B ) $\frac{3}{2}$
( C ) $\frac{2}{3}$
( D ) $3$