Answer: Option (4) is the correct answer.
Step-by-step explanation:
An atom consists of three types of sub-atomic particles which are electrons, protons, and neutrons.
Protons have a positive charge and neutrons have no charge. Whereas electrons have a negative charge.
Protons and neutrons are placed inside the nucleus of an atom. On the other hand, electrons revolve around the nucleus of the atom.
Thus, we can conclude that the structure of an atom is best described as electrons in orbit about a nucleus of protons and neutrons.