Under PL86-272, Which of the Following Transactions by Itself Would Create

Under P.L.86-272, which of the following transactions by itself would create nexus with a state?

A) Inspection by a sales employee of the customer's inventory for specific product lines.
B) Using an independent contractor who acts as a manufacturer's representative for the taxpayer through a sales office in the state.
C) Executing a sales campaign, using an advertising agency acting as an independent contractor for the taxpayer.
D) Maintenance of inventory in the state by an independent contractor under a consignment plan.