The correct answer is: B. Proton, neutron
Protons and neutrons are the two main types of particles found in the nucleus of an atom. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge. The number of protons in the nucleus is called the atomic number, and it determines the chemical element of the atom. The number of neutrons is called the neutron number, and it can vary for atoms of the same element. Atoms with the same number of protons but different numbers of neutrons are called isotopes.
Electrons are found outside the nucleus, in the electron cloud. The number of electrons in an atom is equal to the number of protons in the nucleus, and this is what determines the chemical properties of the atom.
Positrons are the antiparticles of
electrons. They have the same mass as electrons, but they have a positive charge. Positrons are not found in the nucleus of an atom, but they can be created in high-energy collisions.