A binary mixture of butane and butadiene is to be separated in an extractive distillation using furfural. Furfural lowers the activity of butadiene more than it does for butane. Consider the distillation sequence shown in the figure. Match the component labels in Group I with chemical species in Group II. $$\genfrac{}{}{0pt}{}{\textbf{Group I}}{\begin{aligned} P.\ \text{Component X} \\ Q.\ \text{Component Y} \\ R.\ \text{Component Z} \end{aligned}} \qquad\qquad\qquad \genfrac{}{}{0pt}{}{\textbf{Group II}}{\begin{aligned} 1.\ \text{Butane} \ \ \ \ \ \\ 2.\ \text{Butadiene} \\ 3.\ \text{Furfural} \ \ \ \end{aligned}}$$