Task: Question Answering
Input (English): Problem: a train of 25 carriages , each of 60 meters length , when an engine also of 60 meters length is running at a speed of 60 kmph . in what time will the train cross a bridge 2.5 km long ? 
Options: a ) 4 , b ) 3 , c ) 5 , d ) 7 , e ) 9
Output (English): a