The following concentration versus time plot represents the conversion of $$\text{CH}_3\text{NC}(g)$$ to $$\text{CH}_3\text{CN}(g)$$. Which of the following statements is or are true, where 

I is that the reaction is of zero order,

II is that the unit of the rate constant of this reaction is $$\text{s}^{-1}$$, 

III is that the unit of the rate constant of the reaction is torr $$\text{s}^{-1}$$ and 

IV is that the unit of the rate of the reaction is torr $$\text{s}^{-1}$$