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 hollow iron pipe is 21 cm long and its external diameter is 8 cm . if the thickness of the pipe is 1 cm and iron weights 8 g / cm cube , then find the weight of the pipe . 
Options: ['a ) 3.696 kg', 'b ) 3.686 kg', 'c ) 2.696 kg', 'd ) 2.686 kg', 'e ) none of these']

Ex Output:
a


Ex Input:
Problem: due to construction , the speed limit along an 7 - mile section of highway is reduced from 55 miles per hour to 35 miles per hour . approximately how many minutes more will it take to travel along this section of highway at the new speed limit than it would have taken at the old speed limit ? 
Options: a ) 2 , b ) 3 , c ) 4 , d ) 5 , e ) 6

Ex Output:
c


Ex Input:
Problem: a train of length 250 m crosses a bridge of length 150 m in 32 seconds . what is the speed of train ? 
Options: a ) 33 , b ) 27 , c ) 25 , d ) 22 , e ) 45

Ex Output:

e