Final answer:
A silver star is used as a replacement for the specialty mark by the Master Chief Petty Officer of the Navy (MCPON), who is the senior enlisted member of the U.S. Navy.
Step-by-step explanation:
The question is asking about a specific rank distinction within the United States Navy. A silver star replaces the specialty mark for the Master Chief Petty Officer of the Navy (MCPON). The Master Chief Petty Officer of the Navy is the senior enlisted member of the U.S. Navy and serves as an advisor to the Chief of Naval Operations and the Chief of Naval Personnel.