Answer:
I found this online so I hope it can help you but don't copy word for word because it's not my words and I don't know if it's accurate
"The Corps of Discovery were excellent goodwill ambassadors, befriending over 40 tribes while engaging only one in hostilities. The Corps carried a large supply of peace medals, beads, and certificates to help them accomplish this goal. They also recorded valuable information about the tribes and their cultures."
Also I have attached the article link so you can see for yourself
http://corpsofdiscoverydbq.weebly.com/
Explanation:
Go to this website: https://dobleazuniga.wordpress.com/2015/02/13/preguntas-acerca-la-pelicula-agora/
I'd say the correct answer is C. fur trade.
As you already know, Russia is famous for its fur, especially given the temperatures in that country. Fur is important for Russians because they have to warm themselves one way or another. So they obviously wanted to expand into territories where they could continue that trade.