Foods that contain "Big 8" allergens include all but ____.

The option that includes foods least likely to contain "Big 8" allergens is a green salad with oil and vinegar. The "Big 8" allergens refer to the eight major food allergens recognized by the U.S. FDA: milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat.

In this context, a green salad made with oil and vinegar typically consists of various leafy greens and vegetables, which do not include any of these allergens. The dressing of oil and vinegar is also free from these allergens, making the salad a safe choice for individuals with common food allergies.

On the other hand, chocolate chip cookies generally contain wheat (flour) and eggs; cheese and crackers commonly include milk; and fish and chips involve fish, which is another identified allergen. Therefore, the green salad with oil and vinegar stands out as the option least associated with the "Big 8" allergens.