The correct answer is A) Choctaw.
Most of the coal supply that led to mines and mining towns in the Indian Territory was located in Choctaw Indian Nation lands.
By the 1870s, the mining activity in the southern territories was developed mainly in the lands of the Native American Indian tribe known as the Choctaws. The territories of Kansas and Oklahoma have produced most of the coal processed in the United States. James J. McAlester was a big promoter of the mining industry in the region.