Answer:
A.It is made of K and Cl atoms.
Step-by-step explanation:
An atom is the smallest indivisible unit of an element while a molecule is the smallest particle of an element/compound that retains its chemical properties. However, the molecule is two or more atoms held together by means of a chemical bond e.g. Cl2 molecule consists of two atoms of Chlorine.
Hence, if an extended structure dissolves in water to release pottasium (K) and Chlorine (Cl) atoms, it means it is made up of K and Cl atoms. This is because the substance will dissociate l, in the presence of water, into it's simplest form which is the atomic level.