A popular influencer cites a single observational study linking avocado consumption with lower cancer rates and urges followers to eat avocados daily to prevent cancer. Which of the following is the best analytical critique of that claim?

• A. Observational studies inherently prove causation for dietary exposures, so the influencer's claim is definitive and requires no further scrutiny.
• B. Nutrition research is irrelevant for cancer; only genetics matters, so both the observational study and the influencer are making a category error.
• C. Observational association does not establish causation; confounding (e.g., overall healthier lifestyles of avocado eaters), dose, population differences, and reproducibility must be considered before asserting prevention claims.
• D. Since avocados are high in fat, they must cause cancer; therefore any association showing a lower rate is false and should be dismissed without further analysis.

Answer: (C)