Task: Question Answering
Input (English): Problem: a vessel of capacity 50 litres is fully filled with pure milk . nine litres of milk is removed from the vessel and replaced with water . nine litres of the solution thus formed is removed and replaced with water . find the quantity of pure milk in the final milk solution ? 
Options: a ) 23.89 , b ) 72.9 , c ) 33.62 , d ) 78.3 , e ) 79.3
Output (English): c