ANS:C - maximum condenser size.

The minimum reflux ratio in a distillation column typically results in a minimum number of trays required for separation. The reflux ratio (L/D) is the ratio of the liquid returned to the top of the column (reflux, L) to the liquid withdrawn as product from the bottom of the column (distillate, D). It plays a crucial role in determining the efficiency of separation in a distillation column. When the reflux ratio is at its minimum value, the amount of liquid being returned to the column is minimized. Consequently, there is less liquid available to provide the necessary driving force for separation on each tray. As a result, the efficiency of separation is reduced, and more trays are required to achieve the desired separation. In other words, the minimum reflux ratio typically results in a minimum number of trays necessary for achieving separation to meet product specifications. Therefore, the correct statement is: "Minimum reflux ratio in a distillation column results in a minimum number of trays."