Since China adopted its open-door (1) _____ approximately twenty-five years ago

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.

(1) ...............

• A. way
• B. law
• C. rule
• D. policy