The correct option is A Statement I is true and statement II is the correct explanation.
∙ Electron, proton and neutron are the subatomic particles of an atom. A proton carries a unit positive charge, while a electron carries a unit negative charge. A neutron carries no charge.
∙ The number of protons is equal to the number of electrons in a neutral atom.
∙ The charge of protons is balanced out by electrons in a neutral atom. Thus, it carries no net charge. Hence, statement I is true and statement II is the correct explanation.