A、$2.5 an hour. B、$3.75 an hour. C、$5. 15 an hour. D、$7 an hour. C细节题。文章开头处明确提到，在美国，联邦政府规定的最低工资(the federal minimum wage)是每小时5 d

Minimum wage is the lowest hourly pay rate permitted by law.[1]In the United States, the federal minimum wage is 5 dollars and 15 cents an hour. It has not changed since 1997. And it does not include all jobs. For example, workers who re-ceive extra money in the form of tips can be paid 2 dollars and 13 cents an hour. Also, the federal rate may not cover some workers for small companies. State laws often set minimum pay in these cases. Ohio and Kansas have lower minimum wages for some workers than under federal law. But 16 of the 50 states and the District of Columbia have minimum wages higher than the federal one. California’s minimum wage would rise 1 dollar, to 7 dollars and 75 cents an hour, over the next year and a half.
    State governments led the way in the history of the minimum wage in America. Massachusetts passed a law for women and children in 1912.[2]But in 1923, the Supreme Court found wage requirements for private employers unconstitutional. It ruled that states could not interfere with pay agreements. In 1938, however, the Fair Labor Standards Act established a federal minimum wage. At that time, it was 25 cents.
    Some economists and lawmakers argue that markets, but not the government, should set prices for labor.[3]They say minimum wage laws reduce the number of jobs for unskilled workers and young people.
1.How much is the federal minimum wage?
2.What regulation did the Supreme Court make in 1923, according to the passage?
3.What is the effect of minimum wage laws on unskilled workers and young people, according to some economists?