Unlike ionic bonds, covalent bonds involve the

Aloss of one or more electrons from one atom to another.
Bgain of one or more electrons by one atom from another.
Csharing of electrons between atoms.
Ddevelopment of positively and negatively charged ions.

Verified Answer :

An ionic bond is when the atoms transfer electrons, rather than share electrons. This gives the ionically bonded elements a charge. 

Unlike ionic bonds, covalent bonds involve the sharing of electrons between atoms. 

Answer: C. 
 sharing of electrons between atoms.