Answer:
The correct answer is option A. covalent bond.
Explanation:
Bonding between two carbon atoms is a Covalent bond that is also called a carbon-carbon bond. The covalent bond is also known as a molecular bond that forms by the sharing of electron pairs between atoms.
The most common bond between carbon-carbon atom is a sigma covalent bond that involves one electron from both atoms. The three major covalent bonds are the single, double and triple bond.
Thus, the correct answer is option A. covalent.