Which statement among the following is true?

(i) the function $$f(x)=x|x|$$ is strictly increasing on $$R-\{0\}$$.

(ii) the function $$f(x)=\log _{(1 / 4)} x$$ is strictly increasing on $$(0, \infty)$$.

(iii) a one-one function is always an increasing function.

(iv) $$f(x)=x^{1 / 3}$$ is strictly decreasing on $$R$$