Why Is It That in Most of the World, Cities

Why is it that in most of the world, cities have higher turnouts than rural areas?

A) Partly because those who live rurally tend to feel less enfranchised
B) Partly because urbanites on average have higher education levels
C) Partly because people who have lived in the same place are less likely to vote than are transients or newcomers
D) Partly because men tend to vote more than men