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'.

Input: Consider 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

Output: a


Input: Consider Input: Problem: hcf and lcm two numbers are 20 and 396 respectively . if one of the numbers is 36 , then the other number is ? 
Options: a ) 36 , b ) 66 , c ) 132 , d ) 264 , e ) 220

Output: e


Input: Consider Input: Problem: a , b and c can do a piece of work in 7 days , 14 days and 28 days respectively . how long will they take to finish the work , if all the three work together ? 
Options: a ) 4 , b ) 9 , c ) 2 , d ) 11 , e ) none


Output: a