Answer: The correct answer is Atom.
Step-by-step explanation:
Atom consists of proton, electron, neutron and nucleus. The subatomic particles of the atom are electron, proton and neutron.
The electrons revolve around the nucleus while neutrons and protons are located in nucleus. The whole mass of the atom is supposed to be concentrated at nucleus.
The electron is negatively charged particle. The proton is positively charged particle. The neutron has no charge. It is neutral.
Therefore, the correct option is B.