Multi-choice problem: Continue writing the next sentence in this paragraph:

How to clean old leather
Determine what kind of leather you're trying to clean.
Knowing the type of leather you have will help you select the correct cleaning product. Natural or untreated leather does not have a protective coating, while treated leathers do.

Available options:
1). Natural leather is more expensive than store-bought leather, but is more resistant to damage. Check out the leather for air bubbles.
2). Choose a leather cleaner if your leather has the following : An enzyme-based cleaner or a cleaner designed for leather. An oil-based cleaner, such as windex or linseed oil.
3). You can tell that your leather is untreated if it's soft to the touch and doesn't feel like it has a plastic coating. Untreated and natural leathers may change color after you clean them.
4). There are at least two types of leather: non-treated leather and free-to-dry leather. However, if you don't know exactly what kind of leather you have, you may only need to clean leather suitable for your needs.
3).