C. The U.S.
There were several reasons why the United States became interested in revitalizing contact between Japan and the West in the mid-19th century. First, the combination of the opening of Chinese ports to regular trade and the annexation of California, creating an American port on the Pacific, ensured that there would be a steady stream of maritime traffic between North America and Asia. Then, as American traders in the Pacific replaced sailing ships with steam ships, they needed to secure coaling stations, where they could stop to take on provisions and fuel while making the long trip from the United States to China. The combination of its advantageous geographic position and rumors that Japan held vast deposits of coal increased the appeal of establishing commercial and diplomatic contacts with the Japanese.