Final answer:
Option d) provides the best example for sentence (4) regarding the unemployment rate.
Step-by-step explanation:
The sentence that provides the BEST example for sentence (4) regarding the unemployment rate is option d) For example, if there are 100 people in county X, and 20 work for the military, that leaves 80 as the 'total civilian labor force.' If there are 4 unemployed civilians within those 80 people, that means the unemployment rate is 5% (4 divided by 80, or .05).