Your answer is D electron because it gives electrical charges that's why when you touch yours (or someone's) doorknob you sometimes get shock that's because the electrons charge reacted when your hand touch the doorknob which causes it to shock you.
Its not neutrons because they have negative charges (or B)
Its not ions because those are not in atoms (or A)
Its not atom because that's where protons, neutrons, and electrons are at (or C)
Your answer is D.
