Columnist: Metro City has a lower percentage of residents with humanities degrees than any other city of comparable size in our nation. Nationwide, university graduates generally earn more than people who are not university graduates, but those with humanities degrees typically earn less than do graduates with degrees in other disciplines. So the main reason Metro City has higher income per capita than any other city of comparable size in our nation must be its low percentage of residents with humanities degrees.

Which of the following, if true, would most strengthen the columnist's argument?

A. Metro City residents with humanities degrees have higher income per capita than do people with humanities degrees in any other city of comparable size in the nation.

B. The percentage of residents with university degrees is lower in Metro City than in any other city of comparable size in the nation.

C. Nationwide, university graduates without humanities degrees typically earn more than do individuals without university degrees.

D. Metro City residents with degrees outside the humanities have per capita income no higher than the per capita income of such residents of other cities of comparable size in the nation.

E. In Metro City, a lower proportion of university graduates have humanities degrees than in any other city of comparable size in the nation.