Compound A and B are separated by a distillation tower. The ideal mixture follows Raoulfs law and Dalton’s law. The saturated vapor pressure of compound A and B are 75 and 40 mmHg, respectively. The concentration of overhead product, feed, and bottom product are 0.9, 0.5 and 0.1, respectively. The feed is liquid at the boiling point. What is the value of the minimum reflux ratio?
(A) 1.6
(B) 2.1
(C) 1.1
(D) 3.7