The answer is c) electron.
Electrons are negatively charged subatomic particles that orbit around the nucleus of an atom, which is composed of protons and neutrons. Protons carry a positive charge, while neutrons have no charge at all. Together, protons and neutrons are located in the central part of the atom, known as the nucleus, while electrons exist in various energy levels or shells surrounding the nucleus. This arrangement is crucial for the chemical properties of atoms and how they interact with one another.