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: 13 buckets of water fill a tank when the capacity of each bucket is 51 litres . how many buckets will be needed to fill the same tank , if the capacity of each bucket is 17 litres ? 
Options: a ) 39 , b ) 28 , c ) 23 , d ) 12 , e ) 24

Ex Output:
a


Ex Input:
Problem: a can do a piece of work in 8 days and b alone can do it in 12 days . how much time will both take to finish the work ? 
Options: a ) a ) 4.8 , b ) b ) 6.333 , c ) c ) 7.333 , d ) d ) 8.5 , e ) e ) 9

Ex Output:
a


Ex Input:
Problem: what is the cost of leveling the field in the form of parallelogram at the rate of rs . 70 / 10 sq . metre , whose base & perpendicular distance from the other side being 84 m & 24 m respectively ? 
Options: a ) s . 2400 , b ) s . 2016 , c ) s . 1400 , d ) s . 3480 , e ) s . 2000

Ex Output:

b