Final answer:
The scalar chain principle, as defined by Henri Fayol, states there should be a clear and unbroken line of communication from top to bottom in the organization's hierarchy of authority.
Step-by-step explanation:
The correct answer is A. Scalar chain. According to Henri Fayol's principle of scalar chain, there should be a clear and unbroken line of communication from top to bottom in the organization's hierarchy of authority. This means that information and instructions should flow smoothly and directly through each level of the organization, without any bypassing or skipping of levels.