The correct answer is option A.
A chemical bond is a force that holds atoms together in a fixed yet flexible structure.
Chemical bonds are a fixed structure as they are formed by sharing of electrons as in a covalent bond. Chemical bonds are also flexible as they are observed to vibrate by the use of advanced technology such as IR spectroscopy.
According to IR spectroscopy chemical covalent bonds show stretching, rocking, wagging, twisting and scissoring movements.