Answer:
According to APEX, the correct answer would be "All of the above", because Richard Nixon, who became the 37th President of the United States, between 1969 and 1974, decided to take several actions in order to restore positive and peaceful relations with the PeopleĀ“s Republic of China (PRC), communist China, instead of the Republic of China (POC), which had been recognized by the United States as the only government of that country, based in Taiwan, after the Chinese Revolution. In the spirit of gaining a new ally, still in conflict with the USSR, the U.S took advantage of the enmity between communist China and the USSR, and in small, but increasing movements, through his envoy Henry Kissinger, the United States, in the head of Nixon, decided to: lift traveling bans to China, allowed student and tourist interchange between the two nations and ceased any military movements, both in Vietnam, which had been a sore point between the two countries, and near the Chinese waters. This is why the answer, as per APEX, is "All of the Above".