Final answer:
The domain for Karen's homemade blanket business, considering the cost and desired earnings per blanket, is all positive integers.
Step-by-step explanation:
The domain for the situation where Karen is selling homemade blankets and the supplies for each blanket cost her $5.50, and she wants to earn at least $15 for each blanket to compensate for her time, is c) All positive integers. The domain refers to the possible number of blankets she can sell, which would be whole numbers only (you can't sell a fraction of a blanket) and positive because selling a negative amount of blankets doesn't make sense in this context. Therefore, the number of blankets she can sell must be a positive integer.