Sunmart Inc. is a discount retailer with $1,000$ stores across North America. Sunmart purchases bulk quantities of groceries and household goods, and then sells the goods directly to retail customers at a markup. Pharmedical Inc. is a pharmaceutical company that develops medications to prevent and treat diseases, Pharmedical develops, produces, and markets medications for purchase by patients of health$-$care professionals and customers of retail pharmacies and stores. Referring to each company's business model, answer the following:$($a$)$Which company would have a higher gross profit percentage?would have a higher gross profit percentage.$($b$)$Which company would have a higher selling expense as a percentage of sales?would have a higher selling expense as a percentage of sales.$($c$)$Which company would have a higher research and development expense as a percentage of sales?would have a higher research and development expense as a percentage of sales.