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: kathleen can paint a room in 2 hours , and anthony can paint an identical room in 7 hours . how many hours would it take kathleen and anthony to paint both rooms if they work together at their respective rates ? 
Options: a ) 28 / 9 , b ) 4 / 3 , c ) 15 / 8 , d ) 9 / 4 , e ) 15 / 4
Example Output: a

Example Input: Problem: the perimeter of a semi circle is 122 cm then the radius is ? 
Options: a ) 17 , b ) 28 , c ) 24 , d ) 11 , e ) 12
Example Output: c

Example Input: Problem: circular gears l and r start to rotate at the same time at the same rate . gear l makes 10 complete revolutions per minute and gear r makes 40 revolutions per minute . how many seconds after the gears start to rotate will gear r have made exactly 9 more revolutions than gear l ? 
Options: a ) a ) 6 , b ) b ) 8 , c ) c ) 10 , d ) d ) 18 , e ) e ) 15
Example Output:
d