# A can is full of mixture of two liquids A and B in the ratio of 7:5

A can is full of mixture of two liquids A and B in the ratio of 7:5. Whn 9 litres of mixture are drawn off from the can and replaced by the same quantitiy of liquid B, The ratio of A and B in the can becomes 7:9. The capacity of the can is

(a) 10 litres

(b) 21 litres

(c) 20 litres

(d) 36 litres