I'm afraid I couldn't give you a complete answer, or the answer that you're looking for, for this question regarding the Native-born Americans in 1860's since there is no map provided with this question. Try re-posting this question with the map on it.
Answer:
To build Fort Prince George as a way to protect British Territory
Explanation:
I know History I guess?
The answer is A
I found it on quizlet, and it also makes the most sense
I am pretty sure that it is C, I am not 100% sure.