Consider the following reaction: C$_2$H$_5$Cl + AgCN $\xrightarrow{\text{EtOH/H}_2\text{O}}$ X (major). Which one of the following statements is true for X? (I) It gives propionic acid on hydrolysis. (II) It has an ester functional group. (III) It has a nitrogen linked to ethyl carbon. (IV) It has a cyanide group.