Choose the letter A, B, C or D to complete the passage below

Since China adopted its open-door ___(1)___ approximately twenty-five years ago, Chinese higher education has begun once again to draw closer to the ___(2)___ Western world. China's ___(3)___ to send scholars and students to the United States at the end of the 1970s, after thirty years of hostility between the two countries, marked a dramatic turning ___(4)___ in the nation's educational history. Today, about 50,000 Chinese students, are studying in the United States, accounting ___(5)___ 10 percent of the total international students in the country.