There Is a Wealth of Research on the U

There is a wealth of research on the U.S.population showing that people with higher incomes have longer life expectancies.However,if we include gender in the model,the story can become more complicated because men have higher average incomes than women do,but have shorter average lives than women do.Here,we can see that gender could be a suppressor variable of the relationship between income and life expectancy because

A) we are not sure if health affects income or if income affects health.
B) once gender is controlled,life expectancy becomes a lagged dependent variable.
C) being female is still a disadvantage because it is associated with lower average income.
D) being male is positively associated with income,but negatively related with life expectancy.