The first step we have to follow is to draw the structure of this compound and identify its molecular formula:
Isomers are compounds that have the same molecular formula but not the same structural formula. In this case, we have to draw different compounds with the formula C6H10O.
One of them could be cyclohexanone, which has the following molecular structure:
Other isomer could be 2-hexenal, which is an aldehyde with the following molecular structure:
The last isomer can be cyclopentylformaldehyde, which has the following molecular structure: