Answer:
5 isomers
Step-by-step explanation:
In this case, it's very easy to see how many isomers we can form with the molecular formula C7H8O. This is because, the problem already stated that it has to be aromatic.
An aromatic compound has all of it's bond conjugated. In this case, with this hint, we already know that the isomers of this formula it's an aromatic compound of 6 carbons (Because 5 or 7 carbons cannot have conjugated bonds), therefore, the benzene which is the base of an aromatic compound has the formula C6H5. This means that we have left one carbon, 3 hydrogen and 1 oxigen in the formula. So, the remaining carbon would have to be as substituent in the ring, or in another part of the compound, but it's definetly not within the ring. The oxygen can be an alcohol, an ether, or even an aldehyde (And in this case, we use the remaining carbon), or a phenol. So, basing on this, the 5 possible isomers for this formula and aromatic you can see them in the picture attached.
The name of the first compound is the O-methylphenol.