At this point in the paragraph, the writer wishes to emphasize the expansiveness of the Metro system and the coverage that it provides. Which of the following sentences does that best?

A. Each station serves a multitude of travelers.
B. Sometimes, you have to walk as far as nine or ten blocks to get to the nearest Metro station.
C. If you cannot read or understand French, you might have a hard time navigating yourself from station to station.
D. You cannot walk anywhere along the streets of Paris without encountering a staircase that descends to a Metro station.