Task: Question Answering
Input (English): Problem: a tank contains 10,000 gallons of a solution that is 5 percent sodium chloride by volume . if 3,500 gallons of water evaporate from the tank , the remaining solution will be approximately what percent sodium chloride ? 
Options: a ) 6.43 % , b ) 6.89 % , c ) 7.69 % , d ) 8.21 % , e ) 8.75 %
Output (English): c