only its protons only its electrons both its protons and neutrons both its neutrons and electrons
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A student needs to find the mass of an atom. The numbers of which atomic particles determines the mass of the atom?
Possibilities:
- only its protons
- only its electrons
- both its protons and neutrons
- both its neutrons and electrons

both its protons and neutrons