Answer:
Hydroxyl
Step-by-step explanation:
Hydroxyl groups are simple structures consisting of an oxygen atom with two lone pairs bonded to a hydrogen atom.
A hydroxy or hydroxyl group is a functional group with the chemical formula -OH and composed of one oxygen atom covalently bonded to one hydrogen atom.
Using these given definitions, a hydrogen bond is labeled with one linkage, while a covalent bond is with two links to the Carbon Atom.
See attached image for a similar diagram for proof.