Solution:
Concept: The ability of atoms or molecules to combine is measured by their valency. The ability of an atom of one element to interact and combine with a specific number of atoms of another element is what is meant by this definition.Over time, the periodic table's valency first rises and then falls. Going down a group does not bring about change. The polarizability of species is higher and the ionisation energy is lower for elements that are lower in a group for this reason.
The valency of group 2 is and the valency of group 16 is . So, the compound formed is MX. For example: etc.
Hence, the correct answer is option 3.