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 man started driving at a constant speed , from the site of a blast , the moment he heard the blast . he heard a second blast after a time of 30 mins and 25 seconds . if the second blast occurred exactly 30 mins after the first , how many meters was he from the site when he heard the second blast ? ( speed of sound = 330 m / s ) 
Options: a ) 8250 , b ) 9350 , c ) 10,450 , d ) 11,550 , e ) 12,650
Example Output: a

Example Input: Problem: a train 250 m long running at 72 kmph crosses a platform in 15 sec . what is the length of the platform ? 
Options: a ) 50 m , b ) 200 m , c ) 250 m , d ) 270 m , e ) 300 m
Example Output: a

Example Input: Problem: a train after traveling for 50 km meets with an accident and then proceeds at 3 / 4 of its former speed and arrives at its destination 35 minutes late . had the accident occurred 24 km farther , it would have reached the destination only 25 minutes late . what is the speed w of the train . 
Options: a ) a ) 45 , b ) b ) 33 , c ) c ) 48 , d ) d ) 55 , e ) e ) 61
Example Output:
c