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'.

Example Input: Problem: a train 250 m long is running at a speed of 45 km / hr . in what time will it pass a bridge 150 m long ?
Options: a ) 45 sec , b ) 42 sec , c ) 32 sec , d ) 48 sec , e ) 25 sec
Example Output: c

Example Input: Problem: while driving from a - ville to b - town , harriet drove at a constant speed of 105 kilometers per hour . upon arriving in b - town , harriet immediately turned and drove back to a - ville at a constant speed of 145 kilometers per hour . if the entire trip took 5 hours , how many minutes did it take harriet to drive from a - ville to b - town ?
Options: a ) 138 , b ) 148 , c ) 150 , d ) 162 , e ) 174
Example Output: e

Example Input: Problem: how long does a train 110 m long traveling at 60 kmph takes to cross a bridge of 140 m in length ?
Options: a ) 16.5 , b ) 16.0 , c ) 15 , d ) 16.8 , e ) 16.1
Example Output:
c