Final answer:
The appropriate food options for a patient with celiac disease from the given list are Quinoa and tapioca, as they are both gluten-free and safe for individuals needing to adhere to a gluten-free diet.
Step-by-step explanation:
For a patient with celiac disease, the appropriate food options from the given choices would be Quinoa and tapioca. Celiac disease requires a strict gluten-free diet as ingestion of gluten damages the small intestine and impairs nutrient absorption. Quinoa is a gluten-free grain, and tapioca is a starch extracted from cassava root, which also does not contain gluten. However, couscous, made from durum wheat, contains gluten, and while corn is naturally gluten-free, couscous and corn are typically not found paired in a singular diet option. Pure oatmeal is gluten-free, but it is often processed in facilities with wheat, leading to potential contamination. Buckwheat, despite its name, is not related to wheat and is gluten-free; however, care must be taken to ensure it has not been contaminated with gluten from processing alongside gluten-containing grains. Therefore, the safest choices for someone with celiac disease are Quinoa and tapioca.