Final answer:
Carbon monoxide (CO) is a molecular compound because it is composed of carbon and oxygen atoms that are covalently bonded together.
Step-by-step explanation:
Carbon monoxide (CO) is a colorless, odorless, flammable gas that is toxic to humans above 35 ppm in air. The correct answer to the question is that carbon monoxide is a(n) molecular compound. This designation is because it consists of more than one type of element chemically bonded together, specifically carbon (C) and oxygen (O).
Unlike molecular elements, which are composed of only one type of atom, or ionic compounds, which are made up of ions held together by ionic bonds, CO is formed by two non-metal atoms covalently bonded. Thus, it does not qualify as a monatomic element either, as those are single atoms of an element.