A. Plot
Explanation: It is a part of the plot diagram
The Blue Rover in the Donner party had several purposes including being a place of privacy for the women, to carry provisions for the westward trip, to help the Donner party transport their wagons across rivers and for new-comers to the Donner party a refuge.
You didn't underline anything, so we cannot know for sure what the correct answer is. However, I'll just write down the entire infinitive phrases in these sentences, and you can see the answer based on that:
1. to see a great play
2. to cheer good plays
3. to practice until you know all the plays
When he talks about the angry young men, he mentions that the men seek revenge and that this is not what the old men and women would recommend.
He concludes this passage with the words "But let us hope that hostilities between the red-man and his pale-face brothers may never return" - this shows that the correct answer is C.
