Which guideline would show us that tobacco company funded studies about health outcomes of smoking tobacco cigarettes should not be believed? O A. Guideline 5. Beware of confounding variables. If the study neglected potential confounding variables, its results may not be valid. O B. Guideline 2. Consider the source. In particular, look for any potential biases on the part of the researchers. O C. Guideline 6. Consider the setting and wording in surveys. In particular, look for anything that might tend to produce inaccurate or dishonest responses