A. The sentence works fine. one could argue B, but a colon is used to separate a run-on or show two complete thoughts in the same sentence, so arguably B would not work either.
The effect of the Donner party is they stopped at a better location with grazing for cattle and shops for wagon repairs. They planned on going fort Laramie but decided to stop at fort Bernard instead which is 10 miles east of fort Laramie because they were warned that Indians were fighting ahead the grazing for cattle was poor at for Laramie and they could get wagon repairs at fort Bernard.
C because most literature is read by much older people then those who listen to story-telling
I need to see the statement to answer your question.
