Task: Question Answering
Input (English): Problem: a train of length l is traveling at a constant velocity and passes a pole in t seconds . if the same train travelling at the same velocity passes a platform in 5 t seconds , then what is the length of the platform ? 
Options: a ) l , b ) 2 l , c ) 3 l , d ) 4 l , e ) 5 l
Output (English): d