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: in what time will a train 100 metres long cross an electric pole , if its speed be 144 km / hr ?
Options: a ) 2.5 sec , b ) 4.25 sec , c ) 5 sec , d ) 12.5 sec , e ) none

Ex Output:
a

Ex Input:
Problem: the radius of a semi circle is 70 cm then its perimeter is ?
Options: a ) 32.8 , b ) 32.4 , c ) 360 , d ) 32.2 , e ) 32.9

Ex Output:
c

Ex Input:
Problem: if 8 men or 12 women can do a piece of work in 20 days , in how many days can the same work be done by 6 men and 11 women ?
Options: a ) 10 days , b ) 11 days , c ) 12 days , d ) 15 days , e ) 17 days

Ex Output:
c