Revolutionary change can best be described as:

Revolutionary change is characterized as a fundamental challenge to the established order within an organization or system. This type of change signifies a profound and often abrupt transformation that alters the existing structures, processes, and cultural norms. The essence of revolutionary change lies in its ability to disrupt the status quo and redefine the way an organization operates, often in response to significant external pressures, market shifts, or advancements in technology.

In contrast, the other options reflect changes that are more incremental or focused on improving existing practices rather than fundamentally altering them. A gradual evolution of company practices signifies a continuous process of change, but it lacks the disruptive intensity of revolutionary change. Minor adjustments to internal policies indicate small-scale refinements that do not challenge the overarching structure. Similarly, restructuring corporate hierarchy may indicate significant shifts within the organization, but unless it fundamentally challenges the established norms or the overall direction of the organization, it does not encapsulate the essence of revolutionary change. Therefore, the correct understanding of revolutionary change as a profound challenge to the established order highlights its transformative potential and the level of disruption it introduces.