premise: How to choose a kitty litter<br>Go for traditional clay-based litter. Traditionally, cat litter is clay-based. Clay is one of the most popular kinds of litter on the market and is a simple choice that works for most cats.
hypothesis: Cat litter can be made from anything.
reason: The text does not specify all the materials that can be used to make cat litter. It just says it is traditionally made with clay. I don't know why this confused the system.