Question #N331

Gathering accurate data on water flow in the United States is challenging because of the country’s millions of miles of ______ the volume and speed of water at any given location can vary drastically over time.

Which choice completes the text so that it conforms to the conventions of Standard English?
A. waterways and the fact that,
B. waterways, and the fact that,
C. waterways, and, the fact that
D. waterways and the fact that