Write the next sentence in the following story.

How to test for ketones
Take a sample.
You'll need a sample of whatever it is that you are wanting to test for ketones. If your sample is solid, you'll need to dissolve it.

pick from the following.
[1]. To test your sample, scoop it out and use a soft whistle to carefully place a wire rim or metal bowl over the sample. Let it sit for a few seconds to dissolve the test chemical, then remove it, and re-test to see if the sample reacts with the testing powder.
[2]. Sample samples are available at most health food stores. Set the color of your saliva (blood) to the proper color.
[3]. To begin this process, dissolve the sample in water in which it is fresh; if it's solid, you won't get any ketones. While you can find gels and some other good ulcer-friendly products at your local pharmacy, the fda policies can't guarantee results of ketones.
[4]. Do not use a solvent that contains a ketone group (e.g. acetone), or a solvent that will react with a ketone group.. The answer should be
[4].