$38.$ The qualified business income deduction is unavailable to which of the following businesses: a$.$ A sole proprietor dental practice that generates about $$70,000$ in income each year b$.$ A shareholder of an incorporated small tools manufacturer c$.$ A partner in a partnership operated by spouses that sells wood carvings over the Internet

d$.$ A shareholder in an S corporation that owns and operates a restaurant. The S corporation has six different owners.