Definition: In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Input: Problem: a train covers a distance of 12 km in 16 min . if it takes 6 sec to pass a telegraph post , then the length of the train is ? 
Options: a ) 80 , b ) 90 , c ) 60 , d ) 75 , e ) 85
Output:
d