Answer: always available naturally
Step-by-step explanation:
fossil fuels are NON-renewable because we they were here long before us and are not coming back because they aren't natural
inexpensive is wrong because the price value doesn't matter here, it can be any price because it's a product
easy to find is wrong because they don't necessarily have to be easy to find, just available naturally. it can be anywhere and still be a renewable resource because that just means it will come back
therefore "always available naturally" is the correct answer because that's the definition of a renewable resource