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?

Question

Accepted Answer

waterways and the fact that

Answer

waterways and the fact that,

Answer

waterways, and the fact that,

Answer

waterways, and, the fact that