Answer: Option B
Explanation: Electrons, protons and neutrons basically make an atom.
Neutron has no charge - electrically neutral
Protron carries a positive charge
Electron carries a negative charge.
The gain or loss of electrons determines whether an object becomes positively or negatively charged. If there is gain in electron, object becomes negatively charged; if otherwise, it becomes positively charged.
So, it is a function of electron transfer.
The answer is option B