1. What was the Open Door Policy?

The Open Door policy was a statement of principles initiated by the United States in 1899 and 1900. It called for protection of equal privileges for all countries trading with China and for the support of Chinese territorial and administrative integrity.

Explanation:

answer is b.

  it is always the best policy to have good communication and good relations between individuals and, specially, between leaders of the countries. for this purpose, among others, there is a common place, the united nations, where the representants can present his and learn about the other country's policies.