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: 30 buckets of water fill a tank when the capacity of each bucket is 13.5 litres . how many buckets will be required to fill the same tank if the capacity of each bucket is 9 litres ? 
Options: a ) 30 , b ) 32 , c ) 45 , d ) data inadequate , e ) none of these

Ex Output:
c


Ex Input:
Problem: a lady starts from p towards q and realizes that at a point r , if he walks 50 km further he will be at a point s , which is as far away from r as it is from q . what is the distance between p and q if the distance between p and r is half the distance from r to q ? ( assume that p , q , r and s are all on the same straight line ) 
Options: a ) 150 km , b ) 200 km , c ) 250 km , d ) 125 km , e ) 155 km

Ex Output:
a


Ex Input:
Problem: if a train , travelling at a speed of 18 kmph , crosses a pole in 5 sec , then the length of train is ? 
Options: a ) 281 m , b ) 25 m , c ) 50 m , d ) 125 m , e ) 75 m

Ex Output:

b