My clients are not house flippers but when the right opportunity arose to buy a house for a really good price, they jumped on it.  They purchased a run down house and renovated it.  It took over 2 years to renovate it and then they sold it at a profit.  Since they are not flippers and do not intend to do it again, will I report this sale on Schedule D and not C on their 2021 taxes? ( just trying to stay ahead of the game here)