* Compound: A compound is formed when two or more different elements chemically combine in a fixed ratio. Sodium chloride is made up of sodium (Na) and chlorine (Cl) atoms bonded together in a 1:1 ratio.

Let's look at why it's not the other options:

* Element: An element is a pure substance made up of only one type of atom. Sodium chloride has two different elements.

* Homogeneous mixture: A homogeneous mixture has a uniform composition throughout. While table salt might look uniform, it's actually a compound, not a mixture.

* Heterogeneous mixture: A heterogeneous mixture has a non-uniform composition, meaning different parts of the mixture have different properties. Sodium chloride is a compound with a consistent composition.

In summary, sodium chloride is a compound because it is formed by the chemical combination of two different elements.