In El Salvador,a Manufacturer of Household Insecticide Told Dempko Chemical

In El Salvador,a manufacturer of household insecticide told Dempko Chemical Co.'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 D-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) change agent.
B) influential adversary.
C) spotter.
D) gatekeeper.
E) idea champion.