Elizabeth and William just ordered their dream granite countertop from Coronados Inc., which had to purchase the slab, cut it, treat it, and install it. Throughout the process, Elizabeth and William worked with a Coronados salesperson to make sure they chose the right kitchen layout, edging, and other finishes. Here are the costs that Coronados incurred last month to complete 20 kitchen projects like Elizabeth and Williams.\ \ Cost of the stone slabs $27,300\ Overhead costs in fabrication process 3,300\ Commission for salespeople 3,000\ Depreciation on sales and office space 3,100\ Marketing costs 800\ Research and development costs 1,200\ Wages for cutting, treating, and installation labor 18,400\ (a)\ How much of the above cost reflects total product cost for the countertops?\ \ Total product cost $enter the total product cost in dollars\