Answer: A
Explanation:
After a chemical change, the total number of atoms of each elements stays the same.
According to the law of conservation of matter "During a chemical reaction, matter is neither created nor destroyed".
This law provides us with a good view into what happens to atoms after a chemical change.
Simply, since we know that atoms are not created nor destroyed, that means their number cannot increase nor decrease.
The simply remain the same.
This is why every chemical equation must be balanced.
