Answer:
A) Piper or Sarah's income is not affected by her rent income since the cabin was only rented for 14 days and she also used the cabin for personal purposes for more than 14 days.
B) She can deduct mortgage interest ($10,000) and property tax ($1,500), she cannot deduct any other expenses because she is not engaging in any real estate rental activity. These expenses (mortgage interest and property tax) are expenses that anyone can normally deduct from their AGI.