Suppose that we undertake a cohort study to examine the association of high salt intake and hypertension. Our study population consists of male and female Hispanics and Caucasians. No matching or restriction is performed. Lets assume that the following facts are true: Men consume more salt than women. Irrespective of their salt consumption, men have a greater risk of developing hypertension than women. Smokers consume the same amount of salt as non-smokers. Smoking is an independent risk factor for hypertension. Hispanics consume more salt than Caucasians. Irrespective of their salt consumption , Hispanics have the same risk of hypertension as Caucasians. Based on the above information, which of the following are likely confounders in this study?

a.	Gender
b.	Smoking
c.	Race/ethnicity
d.	All of the above