c. Cost- Accounting Method
I would say is best conveyed through one's immediate supervisor. When one would start working in a company, he is under a supervisor that would be the one to convey the messages from the managers. This is done so that the chain of command will not be broken. Since the employee is already given clear instructions is to who he is supposed to answer to, then work related information should be exchanged by the employee and his immediate supervisor so that there is no confusion.
