Answer: The right answer is the Great Plains regions.
Explanation: Ceremonial headdresses, such as feather headdresses or warbonnets, were exclusively worn by a few Indian tribes in the Great Plains region - the Sioux and the Cheyenne among them. Only prominent chiefs and warriors were allowed to wear these sacred and precious objects, and exclusively during formal ocassions. It was an honor to receive and to wear one, and a symbol of courage and bravery. They were often decorated with elaborate and fancy beadwork.