In this task, you need to provide the correct option for a given problem from the provided options.

Problem: in a express train passengers traveling in a . c . sleeper class , first class and sleeper class are in the ratio 1 : 2 : 3 , and fare to each class in the ratio 5 : 4 : 2 . if the income from this train is rs . 57000 , the income of a . c . sleeper class is
Options: a ) rs . 8000 , b ) rs . 12000 , c ) rs . 15000 , d ) rs . 6000 , e ) none
c