5. Calculate the molality of a solution containing 21.2 g of C6H12O6 in 249.6 mL of water (assume the densityof water : 1.00 g/mL; density of the solution : 1.05 g/mL;).
(A) 0.471 m;
(B) 0.435 m;
(C) 0.0783 m;
(D) 0.00841 m;
(E) 0.458 m