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: two cyclist start on a circular track from a given point but in opposite direction with speeds of 7 m / s and 8 m / s . if the circumference of the circle is 630 meters , after what time will they meet at the starting point ? 
Options: a ) 20 sec , b ) 15 sec , c ) 42 sec , d ) 50 sec , e ) 1 min
Example Output: c

Example Input: Problem: if the wheel is 12 cm then the number of revolutions to cover a distance of 1240 cm is ? 
Options: a ) 11 , b ) 14 , c ) 16 , d ) 12 , e ) 19
Example Output: c

Example Input: Problem: a cistern can be filled by a tap in 6 hours while it can be emptied by another tap in 12 hours . if both the taps are opened simultaneously , then after how much time will the cistern get filled ? 
Options: a ) 5.2 hrs , b ) 2.9 hrs , c ) 12 hrs , d ) 7.2 hrs , e ) 1.4 hrs
Example Output:
c