Answer:
A;
Explanation:
The best way to start solving this problem is to start with the molecule with the most atoms. Since there are 12 carbons on the left, you need 12 on the right so 12 would need to be placed in front of carbon dioxide. Also you need 22 hydrogens and in each molecule of water, there are two hydrogen molecules so you need 11 molecules of water. After balancing you find that you need 24 oxygen on the left so you place the coeffecient 12 in front of the oxygen molecule.