And then we have one comma, three one comma, three Hecta, because we have a seven carbon backbone, dying because we have two double bonds. So once again, two double bonds, one on the first carbon, second one on the third carbon, we have an Ethyl group on the third carbon, and we have a seven carbon backbone hepta. So three Ethyl, one three Hepta, dying for this compound. So compound D.
So now we have a ring, a compound, a ring structure. So let's begin labeling on this guy, on this carbon. So 123456.