Question: Which 6.8 mi tributary empties into the Potomac River at the Marine Corps Base Quantico's Air Station near Triangle, Virginia?
Sentence (from "Marine Corps Base Quantico"): Marine Corps Base Quantico, also known as MCB Quantico, is a United States Marine Corps installation located near Triangle, Virginia, covering nearly 55148 acres of southern Prince William County, Virginia, northern Stafford County, and southeastern Fauquier County.
Relevant evidence: Yes