Question: George Drouillard was an interpreter in an expedition which also utilized a specially-established unit of which United States miltary branch?
Sentence (from "George Drouillard"): George Drouillard (1773–1810) was a civilian interpreter, scout, hunter, and cartographer, hired at the age of 30 for Lewis and Clark's Voyage of Discovery to explore the territory of the Louisiana Purchase in 1804–1806, in search of a water route to the Pacific Ocean.
Relevant evidence: Yes