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

How to make aloe vera gel
Wash your hands.
It's important to start with clean hands and use clean tools to make sure the gel doesn't get contaminated.
Slice off an outer leaf of an aloe plant.

Pick your answer from: [I] Use a vegetable peeler or sharp kitchen knife. Put this in the sun and wait a few hours (every 2 hours during the summer months) for the aloe vera gel to develop.. [II] The plant's roots should be intact so cutting them off will only make the gel more bitter. Wash your hands with soap and water.. [III] Peel the outer leaf to get an appropriate base size of gel. Place the cut leaf in a small space.. [IV] The outer leaves are more likely to be mature. They'll contain plenty of fresh, healthy gel..
[IV]