【单选题】

In the United States, boys and girls start school when they are five years olD、In some states they must stay in school until they are sixteen. Most students are seventeen years old when they graduate from secondary school (中学).Another name for secondary school is high school.

Most children go to public elementary schools (小学) and secondary schools. The par- ents of public school pupils do not have to pay directly for these children’s education be- cause tax money supports the public schools. If a child attends a private school, his parents pay the school for the child’s education.
Today about half of the high school graduates go on to colleges and universities. Some colleges and universities receive tax money from the government.
A、student at a state university does not have to pay much if his parents live in that state. Private colleges and universities are expensive, however.Almost half of college students in the United States work while they are studying. When a student’s family is not rich, he has to earn money for part of his college expenses.
The best title for the passage would be______.
A、Schools in the USA
B．Elementary Schools in the USA
C．Secondary Schools in the USA
D．Colleges and Universities in the USA