You haven't included the list of choices that goes with the question, so it's
impossible for me to choose the correct one, or to help you choose it.
Regarding my ability to answer the question and collect the 5-point bounty,
I'm free to make up any phrase of my own that correctly describes an atom.
-- very very very very very very very tiny
-- includes even tinier particles, with electric charges
both positive and negative
-- smaller than the wavelength of visible light
