Increasing the Rate of Higher Education Attainment Among an Area's

Increasing the rate of higher education attainment among an area's adult population has been shown to have what benefit?

A) increases individual incomes and, therefore, income tax revenues
B) strengthens the work force and makes it more appealing to businesses and employers
C) improves an area's civic involvement and, as a result, improves quality-of-life features
D) all of these