The only answer you can pick from that group is atoms, but it is a shaky answer. It's just that nothing else is appropriate. Hydrogen won't work C-Cl4 is a molecule. No hydrogen.
Minerals. Again CCl4 does not contain any minerals.
Gas: Doesn't work. Many things (perhaps even the majority of compounds) are not gaseous. For example NaCl is table salt. It's a solid
Answer: Choose C. Ions are what make me hesitant.