Covalent bonds are intermolecular bonds which involve the sharing of electrons between atoms or molecules and ions with close or near electronegativity values.
This usually form molecules. This is also the sharing of electrons donated by one of the atoms or by both of the atoms to form a molecule and at the same time obtain a stable octet state.
The correct response I believe is A. Isomer. If a carbon molecule possess more than one arrangement of how its atoms can be arranged, those other arrangements are known as isomers.
