Final answer:
Cut potatoes should be submerged in enough cold water to cover them completely. The reference to 'three feet' is incorrect for kitchen practices; a few inches of water is typical.
Step-by-step explanation:
All cut potatoes must be submerged in cold water to prevent oxidation, which can cause discoloration and affect their taste and texture. For food safety and quality, the potatoes should be completely covered with water. However, the provided reference mentioning 'three feet' is likely inaccurate as that would be impractical in a typical kitchen setting. Instead, cut potatoes are usually submerged in enough cold water to completely cover them, which is typically just a few inches above the potatoes, depending on the size of the container.