Mad Hatters, Inc. is a costume store based in Navajo County, Arizona. It has stores in Navajo, Maricopa, Pima and Pinal counties. Xeon Corporation entered into a contract for Mad Hatters to furnish 75 costumes for an ad campaign. Xeon has its headquarters in Maricopa County, but has offices in Pima and Navajo Counties. Xeon has failed to pay for the costumes. Mad Hatters has brought suit in Superior Court, the trial court for Arizona. The county in which the suit is held is a question of: a. venue. b. fact. c. federal jurisdiction. d. none of the above