It's A as to the avoiding double negation which is not possible in English.
The purposes of sentences 3-6 is to describe in detail what the outside
of the cottage looks like. The description paints a clear image in the
readers head of specific details and surroundings in and around the
outside of the cottage. It adds vivid imagery which also makes the
paragraph more interesting. So they provide supporting details
I think it's C) To describe the life of the Cherokee tribe...
I'm not sure though
I do not specialize in this subject but if u go to tutor and search the subject you can talk them