Answer:
D. The number of atoms in the reactants equals the number of atoms in the products.
Step-by-step explanation:
A chemical equation can be defined as a reaction between two chemical elements.
The condition which must be met in order for an equation to be balanced is that, the number of atoms in the reactants equals the number of atoms in the products.
This ultimately implies that, the mass and charge of the chemical equation are both balanced properly.