Task: Question Answering
Input (English): Problem: the r train leaves station a moving at a constant speed , and passes by stations b and c , in this order . it takes the r train 7 hours to reach station b , and 5 additional hours to reach station c . the distance between stations a and b is m kilometers longer than the distance between stations b and c . what is the distance between stations a and c in terms of m ? 
Options: a ) 1.8 m , b ) 6 m , c ) 7 m , d ) 9 m , e ) 12 m
Output (English): b