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

Example Input: Problem: the contents of two vessels containing copper and tin in the ratio 1 : 2 and 2 : 5 are mixed in the ratio 1 : 4 . the resulting mixture will have copper and tin in the ratio ? 
Options: a ) 15 : 32 , b ) 21 : 28 , c ) 31 : 74 , d ) 33 : 37 , e ) 41 : 92
Example Output: c

Example Input: Problem: divide rs . 32000 in the ratio 3 : 3 ? 
Options: a ) 12000 , 20000 , b ) 12000 , 200098 , c ) 16000 , 16000 , d ) 12000 , 20006 , e ) 12000 , 20001
Example Output: c

Example Input: Problem: water consists of hydrogen and oxygen , and the approximate ratio , by mass , of hydrogen to oxygen is 2 : 16 . approximately how many grams of oxygen are there in 180 grams of water ? 
Options: a ) 160 , b ) 72 , c ) 112 , d ) 128 , e ) 142
Example Output:
a