The Treaty of Wang-hsia in 1844, which gained the United States expans

The Treaty of Wang-hsia in 1844, which gained the United States expansive trading rights in China, was made possible by

A) Britain forcing China to open its ports to the West as a consequence of its military victory in the Opium War (1839-1842).
B) a change in the Qing regime’s political leadership in China, bringing to power an emperor committed to upholding liberal trading rights with the West.
C) the United States threatening a naval embargo of China unless it agreed to provide access at its ports to U.S. commercial ships containing manufactured goods and food.
D) the influence of Protestant missionaries in changing the views of the Qing regime about providing access to U.S. commercial ships.

ANSWER
Answer: A