Final answer:
JREAP Category C is the protocol used for multi-participant satellite communication networks within the military for exchanging digital data reliably.
Step-by-step explanation:
The Joint Range Extension Application Protocol (JREAP) that uses communication links which are multi-participant satellite communication networks is JREAP Category C. JREAP is used extensively for enabling digital data exchange between tactical data systems, particularly in military settings where reliable communication is crucial. There are three categories of JREAP: Category A (point-to-point serial data links), Category B (IP networks), and Category C. It is Category C that is specifically designed for use with synchronous and asynchronous satellite, line-of-sight, and other communication networks supporting multiple participants.