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: on my sister ' s birthday , she was 132 cm in height , having grown 10 % since the year before . how tall was she the previous year ? 
Options: a ) 130 cm , b ) 126 cm , c ) 120 cm , d ) 116 cm , e ) 112 cm
Example Output: c

Example Input: Problem: a tank is 25 m long 12 m wide and 6 m deep . the cost of plastering its walls and bottom at 75 paise per sq m is 
Options: a ) rs . 258 , b ) rs . 358 , c ) rs . 458 , d ) rs . 558 , e ) none of these
Example Output: d

Example Input: Problem: a man started driving at a constant speed , from the site of a blast , the moment he heard the blast . he heard a second blast after a time of 30 mins and 24 seconds . if the second blast occurred exactly 30 mins after the first , how many meters was he from the site when he heard the second blast ? ( speed of sound = 330 m / s ) 
Options: a ) 6810 , b ) 7920 , c ) 9030 , d ) 10,140 , e ) 11,250
Example Output:
b