The sioux and sitting bull led the attack on general george armstrong custer's cavalry at the battle of little big horn. why did the sioux take this course of action? a) general custer wanted congress to outlaw the sioux's ritual ghost dance. b) the transcontinental railroad was moving through the area the sioux inhabited. c) sioux leaders had forged a military alliance with french canadian forces in an attempt to take back land. d) the u. s. government had broken promises to let the sioux remain in the black hills and was attempting to force them from those lands.