Task: Question Answering
Input (English): Problem: 3 persons invested rs . 9000 in a joint business . the second person invested rs . 1000 more than the first and the third rs . 1000 more than second . after two years , they gained rs . 1800 . how much third person will get ? 
Options: a ) 400 , b ) 800 , c ) 600 , d ) 1200 , e ) 1000
Output (English): b