Because it was done that way to spread fear and send a message.
It wasn't simply murder, it was a statement.
Jan 17, 1706 - Apr 17, 1790 (age 84)
B, it was when the western pioneers moved east to discover new land to grow crops and make population XD
I believe the answer would be: C. Custer and his force arrived ahead of the main U.S. force.