$1.$The minimum reflux ratio in a distillation process is important because:

A$)$ It represents the most energy$-$efficient operation.

B$)$ It is the point where the number of stages is infinite.

C$)$ It defines the maximum separation achievable.

D$)$ It is the easiest operating point to maintain.

Multiple feeds in a distillation column:

A$)$ Can only be introduced at the top of the column.

B$)$ Require separate columns for each feed.

C$)$ Are used to introduce feeds at different stages.

D$)$ Decrease the efficiency of separation.

Side streams in distillation are used to:

A$)$ Withdraw products at different purity levels.

B$)$ Introduce additional reflux.

C$)$ Increase the relative volatility.

D$)$ Reduce the number of stages required.

The Gilliland correlation relates:

A$)$ The minimum to the actual number of stages.

B$)$ The minimum reflux ratio to the actual reflux ratio.

C$)$ The feed quality to the stage efficiency.

D$)$ The distillate to bottoms ratio.