Inside the distillation columns, the

Answer: Option D

Option D: All of the above is the correct answer.

Option A: Highest temperature is near the feed plate
This is true because the feed plate is generally located between the rectifying and stripping sections. Since the bottom of the column is hotter (to vaporize the liquid) and the top is cooler (to condense vapors), the feed plate lies between these extremes and usually has a relatively high temperature, especially in comparison to the overhead.

Option B: Driving force for the liquid flow is its weight
This is correct. In a distillation column, the trays are arranged vertically, and gravity causes the liquid to flow from one tray to the next lower one through downcomers. Thus, the liquid flow is driven by its weight.

Option C: Vapors are not always at their dew points
Also true. Vapors in the column can be superheated or in equilibrium with liquid depending on the location and thermal gradients. Therefore, they are not necessarily always at their dew point.

Since all the individual statements are correct, the correct answer is: Option D: All of the above.