Final answer:
The national minimum wage in the United States is $7.25 per hour, a rate set in 2009. There is a debate about its adequacy due to the rising cost of living and its relation to the poverty line (option B).
Step-by-step explanation:
The United States national minimum wage is $7.25 per hour. This rate was established in mid-2009 and is a price floor that makes it illegal for employers to pay employees less than this hourly rate. The concept of the minimum wage is that someone working full-time should be able to afford a basic standard of living. However, there is an ongoing debate about whether $7.25 per hour is sufficient, with many suggesting it is too low to meet the rising costs of living, as working 40 hours a week at this rate for 50 weeks a year yields an annual income of $14,500, which is below the poverty line for a family of four.
Hence, the answer is option B.