Answer: The correct answer is Option A.
Explanation:
Covalent compound is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound. These are usually formed when two non-metals react.
An ionic compound is defined as the compound which is formed when electron gets transferred from one atom to another atom. These are usually formed when a metal reacts with a non-metal or a metal reacts with a polyatomic ion or a reaction between two polyatomic ions takes place.
For the given options:
Sulfur and fluorine, both are non-metals and they will form a covalent compound.
This compound is formed by the combination of [tex]NH_4^+\text{ and }OH^-[/tex] ions. These two are polyatomic ions and thus will form an ionic compound.
This compound is formed by the combination of aluminium which is a metal and [tex]CN^-[/tex] ion which is a polyatomic ion. Thus, it will form an ionic compound.
This compound is formed by the combination of cobalt which is a metal and nitrogen which is a non-metal. Thus, it will form an ionic compound.
Hence, the correct answer is Option A.
