Answer:
The correct answer is the option C: working the grapevine.
Step-by-step explanation:
To begin with, in the field of management, the term of ''grapevine communication'' refers to the informal dialogue in its purest form in the workplace and whose main purpose is to establishes relations through communications between superiors and employees that do not follow any type of structured system.
To continue, Ernesto is working the grapevine when he is trying to communicate with Vonnie in order to understand better what his employees think about the new pension plan.