Answer:
alcohol
Step-by-step explanation:
Functional group of an organic compound is that part of its structure that contains atoms, which determines its characteristic chemical properties. The functional group is what makes an organic molecule UNIQUE and different from others.
In the structure displayed in the attachment, the functional group is identified as -OH. R-OH is the functional group for ALCOHOLS, which compounds like ethanol, butanol etc fall into. Specifically, the structure in the attachment is METHANOL.