In El Salvador, a manufacturer of household insecticide told Dempko Chemical Company's salesperson Nelson Viquez that it wanted a substitute for the kerosene it always used in making aerosol household insecticide. Viquez worked extensively with the manufacturer to create a pilot plant and test its pesticides with the addition of Dempko Chemical's Demosol Dâ€"a substitute for kerosene. Dempko Chemical and the manufacturer spent a year and a half running laboratory and field tests on the new product, which was extremely successful in Central America. Viquez acted as a(n):.a. spotter. b. gatekeeper. c. change agent. d. idea champion. e. influential adversary.