Final answer:
Subordinate leaders in mission command must exercise disciplined initiative at all echelons to be successful. This empowers them to make and act upon decisions aligned with their superior's intent, adapting effectively to dynamic situations.
Step-by-step explanation:
For mission command to be successful, the statement that best describes what is demanded by subordinate leaders is C. The exercise of disciplined initiative at all echelons. Mission command relies not just on a hierarchy of authority, but on the ability of leaders at all levels to understand their superior's intent and to take decisive action within the bounds of that intent, even without direct orders. This requires a balance of authority and autonomy. Leaders must be empowered to make critical decisions and act on them swiftly to adapt to changing situations on the ground. A successful command structure is one where subordinates are trained and trusted to execute their tasks with a level of independence, ensuring the broader mission objectives are achieved efficiently and effectively. Disciplined initiative is a key aspect of this, as it combines the understanding and adherence to military discipline with the agility to respond proactively to unforeseen circumstances.