The U.S. birthrate began to decline in the middle 1950's, resulting in a smaller College a

ge population starting in the middle 1970's. Something else happened in the 1970's: the price of oil increased tremendously, driving up the price of almost everything and making Americans aware that their large automobiles used a lot of gasoline. At the same time, foreign car manufacturers had begun to produce small fuel efficient cars in large quantities for the export market. Suddenly, the large, gas guzzling American cars were no longer attractive to American buyers, who began buying foreign cars by the thousands. The American automobile industry went into a recession. Thousands of automotive workers were laid off, as were thousands of people in industries indirectly connected with the auto industry. People who are laid off tend to keep what money they have for necessities, like food and housing. They do not have the extra money needed to send their children to college. Their children cannot pay their own college costs, because during a recession they cannot find jobs. High unemployment means that more state funds must be used for social service—unemployment benefits and to aid dependent children, for example—than during more prosperous times. It also means that the states have fewer funds than usual, because people are paying fewer taxes. Institutions of higher education depend on two major sources of income to keep them functioning: tuition from students and funds from the states. At the present time, there are fewer students than in the past and fewer state funds available for higher education. The colleges and universities are in trouble.

What is the main idea of this passage？

A．The rising of oil price drove up the price of everything.

B．There were many reasons why higher education was in trouble in the 1970's.

C．Birthrate began to decline in the U.S.A. in 1950's.

D．High unemployment caused a lot of social problems.