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'.

Example Input: Problem: a car runs at the speed of 25 km per hour when not serviced and runs at 75 kmph when serviced . after servicing the car covers a certain distance in 5 hours . how much time will the car take to cover the same distance when not serviced ? 
Options: a ) 8 hours , b ) 16 hours , c ) 15 hours , d ) 7 hours , e ) none
Example Output: d

Example Input: Problem: one hour before john started walking from p to q , a distance of 23 miles , ann had started walking along the same road from q to p . ann walked at a constant speed of 3 miles per hour and john at 2 miles per hour . how many miles had ann walked when they met ? 
Options: a ) 6 miles , b ) 8,4 miles , c ) 9 miles , d ) 9,6 miles , e ) 15 miles
Example Output: e

Example Input: Problem: the difference between the squares of two consecutive numbers is 35 . the numbers are 
Options: a ) 14,15 , b ) 15,16 , c ) 17,18 , d ) 18,19 , e ) none
Example Output:
c