Answer:
1. C. to trade with people following Lewis and Clarks trail
2. A. he arranged for a sea expedition to the mouth of the Columbia river
3. D. treaty of Ghent
Step-by-step explanation:
1. John Astor plans to establish a trading post at the mouth of the Columbia river because he wants "to trade with people following Lewis and Clark's trail."
This is evident when in April 1811, he created a company named Astoria, a Pacific Fur comoany for the purpose of trading Fur
2. The accomplishment of David Thompson was that he "arranged for a sea expedition."
This is evident when he along with nine others set out and eventually arrived at the mouth of the Columbia on the Pacific Ocean on July 14, 1811,
3. The Treaty of Ghent is what ended the war of 1812.
This treaty settled the boundary issue between the United States and Canada. It started that all conquered territory should be returned.