Task: Question Answering
Input (English): Problem: if grapes are 91 % water and raisins are 19 % water , then how many kilograms did a quantity of raisins , which currently weighs 9 kilograms , weigh when all the raisins were grapes ? ( assume that the only difference between their raisin - weight and their grape - weight is water that evaporated during their transformation . ) 
Options: a ) 63 , b ) 72 , c ) 81 , d ) 90 , e ) 99
Output (English): c