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'.

Ex Input:
Problem: a 250 meter long train crosses a man standing on the platform in 12 sec . what is the speed of the train ?
Options: a ) 228 , b ) 108 , c ) 1266 , d ) 75 , e ) 211

Ex Output:
d

Ex Input:
Problem: it takes 35 identical printing presses 12 hours to print 500,000 papers . how many hours would it take 30 of these printing presses to print 500,000 papers ?
Options: a ) 14 , b ) 15 , c ) 16 , d ) 18 , e ) 20

Ex Output:
a

Ex Input:
Problem: a man rows his boat 70 km downstream and 45 km upstream , taking 2 1 / 2 hours each time . find the speed of the stream ?
Options: a ) 1 kmph , b ) 6 kmph , c ) 5 kmph , d ) 8 kmph , e ) 7 kmph

Ex Output:
c