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.
waterways and the fact that,
waterways, and the fact that,
waterways, and, the fact that
waterways and the fact that
Choice D is the best answer. The convention being tested is punctuation within two coordinated noun phrases. When, as in
this case, a noun phrase (“the country’s millions of miles of waterways”) is coordinated with another noun phrase (“the fact”)
followed by an integrated relative clause (“that the volume...time”), no punctuation is needed.
Choice A is incorrect because no punctuation is needed. Choice B is incorrect because no punctuation is needed. Choice C
is incorrect because no punctuation is needed.