阅读理解。阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。
In the United States, there were some well-constructed houses for native Indians, ranging from the simple brush shelter to the five-storied pueblo.
In the eastern United States, one of the existing types was that commonly know under the Algonkian name of wigwam in which the Iroquois Indians lived. The wigwams were of wagon-top shape with straight sides and ends, made by bending young trees to form the round shape. Over this shape pieces of tree bark were laid to protect the Indians from bad weather. Over the bark dried grass was added. A small hole allowed smoke to escape from the top. Doorways at each end served also as windows, The Iroquois Indians built trunk walls all around their villages. The wall had only one opening, They could quickly close this opening if their enemies came near.
Interestingly, the Choctaw Indians in Mississippi also lived in a wigwam of a most primitive(原始的) construction, but different from those of the Iroquois Indians. The Choctaw Indians’ wigwams, made from mud, cane and straw, were in the form of a bee-hive. The covering was made of a long, tough grass. A post in the centre supported the roof. A hole in the top admitted the light, and allowed the smoke to pass out.
