Hmm ....

The starting point is conveniently working out with the "double bond equivalent" from the molecular formula. This shows the presence of one "double bond" or its equivalent of a ring.

Strong supporting evidence for the stucture could be obtained by looking at the infrared spectra. Those compounds containing a C=O group would show a strong peak at 1650-1750 cm-1, whilst those having an O-H group would show bands at 3400 cm-1.