92. Solving a chemistry problem

15. Up to 2.0% nitrobenzene remains in the spent nitrating mixture after distillation with water vapor. What amount of nitrobenzene can be extracted from 1 m3 of such a mixture by extraction with benzene (K-1.0*10-5) at an extractant consumption in a volume ratio to the mixture of 1/5 and an effective number of extraction stages equal to A) 1.0 B) 2.0 B) 3.0