In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: drum x is 1 / 2 full of oil and drum y , which has twice the capacity of drum x , is 1 / 5 full of oil . if all of the oil in drum x is poured into drum y , then drum y will be filled to what capacity ? 
Options: a ) 3 / 10 , b ) 7 / 10 , c ) 9 / 10 , d ) 9 / 20 , e ) 13 / 20
Example Output: d

Example Input: Problem: a dog is tied to a tree by a long nylon cord . if the dog runs from the due north side of the tree to the due south side of the tree with the cord extended to its full length at all items , and the dog ran approximately 30 feet , what was the approximate length of the nylon cord e , in feet ? 
Options: a ) 30 , b ) 25 , c ) 15 , d ) 10 , e ) 5
Example Output: d

Example Input: Problem: the mean of 50 observations is 200 . but later he found that there is decrements of 9 from each observations . what is the the updated mean is ? 
Options: a ) 165 , b ) 185 , c ) 190 , d ) 191 , e ) 199
Example Output:
d