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: jake can dig a well in 16 days . paul can dig the same well in 24 days . jake , paul and hari together dig the well in 8 days . hari alone can dig the well in
Options: a ) 96 days , b ) 48 days , c ) 32 days , d ) 24 days , e ) 28 days

Ex Output:
b

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 walks at 30 kmph and 30 hours after his start , b cycles after him at 45 kmph . how far from the start does b catch up with a ?
Options: a ) 1200 km , b ) 1500 km , c ) 2000 km , d ) 2700 km , e ) 3600 km

Ex Output:
d