A multiple regression predicting tech salaries obtains an insignificant (zero) coefficient on age and a significantly negative coefficient on being foreign-born. A simple regression of tech salaries on age obtains a significantly positive coefficient on age. These results can be explained if _____.

Group of answer choices

age is unrelated to being foreign-born

the simple regression coefficient is unbiased

foreign-born tech workers tend to be younger than non-foreign-born

foreign-born tech workers tend to be older than non-foreign-born