Rockville Enterprises manufactures woodworking equipment and is incorporated and based in Evansville, Indiana. All of itsreal property is in Indiana. Rockville employs a large sales force that travels throughout the U. S. Determine whether each of the following is a protected activity in nondomiciliary states under Public Law 86-272: a)Rockville advertises in Wisconsin using television, radio and newspapers. b) Rockville’s employees in Illinois check the credit of a potential customer. c) Rockville maintains a booth at an industry tradeshow in Arizona for 10 days. d)Sales representatives check the inventory of a Tennessee customer to make sure it has enough in stock and that the stock is properly displayed. e) Rockville holds a management seminar executive retreat for corporate executives over four days in Florida.