In addition to monitoring channel 16, all Corps of Engineer locks may use as working channels __________.

Correct Answer: Option B — 12, 13 and 14

U.S. Army Corps of Engineers locks utilize VHF-FM channels 12, 13, and 14 for bridge-to-bridge and lock-to-vessel communications. These channels are designated to ensure safe transit and coordination within the lock approach and chamber, as specified in the USCG Navigation Rules and the U.S. Coast Pilot.