Who fought in the Opium Wars? What caused them?

The opium wars were fought between China and the Western powers.

Explanation:

During the 19th century, two opium wars were fought. The main actors were China and the United Kingdom. The British had a deficit with importing Chinese tea, so they tried to make a trade balance by exporting opium to China. Opium had a bad effect on people, so the Chinese authorities decided to ban the consumption and import of opium. In such circumstances, they conflict with the British, who were militarily superior and defeated China. The Chinese continued to insist on trade closed. They refuse to establish foreign embassies in the country. In such circumstances, a new conflict ensues where Britain was joined to a lesser extent by Russia and the United States. China is defeated again, and the Chinese authorities had to accept all the conditions imposed after the war.

d

Explanation:

Technically its the northwestern and western part of Mexico (Rio) and Texas but that answer suffices.