Republican-leaning counties in Maryland outnumber Democrat-leaning counties, yet more of the state's U. S. representatives are Democratic rather than Republican. What is the most likely explanation for this circumstance?

A. Congressional districts in large population centers each elect
more than one representative.

B. Counties are only important during U. S. presidential elections, not
congressional elections.

C. Congressional districts are proportionate to the population, which
is mostly Democratic.

D. The size of counties in mileage is more important than the number
of counties