In 1899 and 1900, what did u. s. secretary of state john hay do?

The correct answer is Asked china to keep its ports open to western trade in return for guarantees made by the European powers

He was an advocate of the Open-door policy in trading with the Chinese people and government. This meant that China would not employ protectionism towards anyone from Europe or anywhere else and would give equal trading rights to anyone who wanted to trade with it. China would thus be a haven for merchants and not just a partner to one country.