Q. Pick out the correct statement.

• (A) The slope of the stripping line is always less than unity
• (B) For a given separation in a binary distillation column, with increase in reflux ratio (above the minimum reflux ratio), the fixed cost of the distillation column first increases and then decreases
• (C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux
• (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower