B). Nixon’s visit to China opened up foreign relations and US-China economic ties.
Explanation:
Nixon's visit to China brought a significant change in foreign relations and strengthened the U.S - China economic ties even till today. Also, it helped to open Soviet concessions to the U.S.
As the visit opened up China, it resulted in the U.S. gaining more leverage with her relations with the Soviet Union. The visit made China to be removed from the Cold War foe list.
It all brought in fresh air in the U.S-China relationship.
