Which statement about the balanced equations for nuclear and chemical changes is correct?

Question

A chemical equation is balanced according to a mass number. A nuclear equation is balanced according to the total mass before and after the change.
Both are balanced according to the mass number of each element before and after the change.
A nuclear equation is balanced according to mass number. A chemical equation is balanced according to the total mass before and after the change.
Both are balanced according to the total mass before and after the change.

Answer 1

The most accurate statement is:

A nuclear equation is balanced according to mass number. A chemical equation is balanced according to the total mass before and after the change.

This means that in a nuclear reaction, both the mass number and atomic number must be conserved, while in a chemical reaction, the total mass of the reactants must equal the total mass of the products, consistent with the conservation of mass.