Answer: The answer is the second option, located important routes for trade and travel. The expedition was commissioned by President Thomas Jefferson immediately after the Louisiana Purchase in 1803. It was composed of a select group of volunteer officers of the United States Army under the command of Captain Meriwether Lewis and his friend, Second Lieutenant William Clark. Their dangerous journey lasted from May 1804 to September 1806. The main objective was to explore and map the newly acquired territory, open a safe route through the western half of the continent and establish American presence in the extensive area before Great Britain or other European claimed it.