After 1570, Why Was Japan Supplanted as the Primary Source

Multiple Choice

After 1570, why was Japan supplanted as the primary source of silver for China?

A) The Spanish discovered new sources of silver in the Philippines, which was closer to China than Japan was.
B) The Japanese closed their doors to all external trade, in order to avoid European domination.
C) The Spanish took control of the Philippines and used it as a conduit for silver from their colonies in the Americas.
D) Japanese silver was mined out, leaving them with little to trade internationally.