Process of elimination. There is more than just water vapor in a vape so it can't be D, it isn't a cigarette so it can't be B, and A is just clearly not the answer haha.
These two are elements. Meaning tget are substances that cannot be broken down because they are pure. The others are considered molecules due to their ability to be broken down.
Covalent molecular structures are compounds containing molecules with covalent bonds. Covalent network structures are compounds composed of a network structure with covalent bonds between atoms throughout the material.
