Reaction A: Total mass Remains Unchanged.... Which of these statements best explains the identity of Reaction A?

Reaction A: Total mass Remains Unchanged....

best

 It is a nuclear reaction because the total mass remains the same when there is a change in the number of protons and neutrons.

 It is a chemical reaction because the total mass remains the same when the nuclei of the atoms reacting split.

 It is a nuclear reaction because the total mass remains the same when there is a change in the overall energy of the system.

 It is a chemical reaction because the total mass remains the same when new substances are formed.