Which of the following represents the simplest form of a chemical compound?

The simplest form of a chemical compound is represented by the empirical formula. This formula provides the lowest whole-number ratio of the elements present in the compound without indicating the actual number of atoms or the arrangement of those atoms. For example, in glucose (C6H12O6), the empirical formula is CH2O, reflecting the simplest ratio of carbon, hydrogen, and oxygen atoms.

In contrast, the molecular formula would indicate the actual number of atoms in the molecule, while the structural formula shows how the atoms are arranged and connected in the molecule. The concentration formula pertains to the amount of a substance in a given volume of solution and does not describe the composition of a chemical compound itself.

Thus, the empirical formula is the correct choice as it embodies the simplest representation of a chemical compound’s composition.