One major problem facing the county governments with cities like Las Vegas, Phoenix, and San Antonio is rapidly increasing populations. Option B is correct.
The 2010 Census reported 308.7 million people in the United States, a 9.7 percent increase from the Census 2000 population of 281.4 million.
According to the census, Nevada was the fastest-growing state between 2000 and 2010, growing by 35.1 percent.
The ten most populous states home 54.0 percent of the U.S. population in 2010.