Answer : Option D) Covalent bond.
Explanation : The bond formed when electrons are shared is called a covalent bond.
A covalent bond which is also called as molecular bond, is a chemical bond which involves mainly the sharing of electron pairs between atoms. These electron pairs are called as shared pairs or bonding pairs, which are stable balance of attractive and repulsive forces between atoms, when these bonding pairs share electrons, it is called as covalent bonding.
Covalent bonding is usually seen in non-metals which share their electrons while bonding.
