A、People with high diplomas. B、People with good salaries. C、People valuable to the gross national product. D、People specialized

In America, when your parents advise you to "get an education" in order to raise your income, they only tell you half the truth. (33)What they really mean is to get just enough education to provide the manpower for the society.
    Get a high school diploma, at least. Without that, you will be occupationally dead unless your name happens to be George Bernard Shaw. Get a college degree, if possible. With a B. A. , you are on the launching pad. But now you have to start to put on the brakes. If you go for a master’s degree, make sure it is an MBA, and is famous. A Ph. D. is the highest degree you can get. (34)Except for a few specialized fields such as physics or chemistry where the degree can quickly be turned to industrial or commercial purposes, if you pursue such a degree in any other field, you will face a dim future. If you become a doctor of philosophy in English or history or anthropology or political science or language or—worst of all—in philosophy, you run the risk of becoming overeducated for what US demands. Thousands of Ph. D. s are selling shoes, driving cars, waiting on tables, and endlessly filling out’applications month after month. They may also take a job in some high school or backwater college that pays much less than the door-keeper earns.
    You can equate the level of income with the level of education only when you are useful to the gross national product.
33. Q: What does American parents really mean when they tell you to "get an education"?
34. Q: According to the author, what kind of Ph. D. will have a bright future?
35. Q: How can one equate the level of income with the level of education?