In this task, you need to provide the correct option for a given problem from the provided options.

Example Input: Problem: the present ratio of students to teachers at a certain school is 30 to 1 . if the student enrollment were to increase by 50 students and the number of teachers were to increase by 5 , the ratio of students to teachers would then be 25 to 1 . what is the present number of teachers ? 
Options: a ) 5 , b ) 8 , c ) 10 , d ) 12 , e ) 15
Example Output: e

Example Input: Problem: a ratio between two numbers is 4 : 5 and their l . c . m . is 200 . the first number is 
Options: a ) 60 , b ) 40 , c ) 20 , d ) 15 , e ) none
Example Output: b

Example Input: Problem: divide rs . 116000 among 3 persons a , b and c such that the ratio of the shares of a and b is 3 : 4 and that of b : c is 5 : 6 . find the share of a ? 
Options: a ) 29491 , b ) 28491 , c ) 39491 , d ) 49491 , e ) 59491
Example Output:
a