What was the policy that ensured all nations would have equal trading rights in all spheres of influence?

a) fair trade policy

b) sphere of influence policy

c) closed door policy

d) open door policy

The Open Door policy originated in the treaty port system that emerged in China during the 1840s. For centuries, China had resisted the efforts of Western traders to penetrate the country, restricting their activities to the port of Canton (Guangzhou) and subjecting them to severe punishment for violation of Chinese law. Following Britain's sweeping military victory over China in the First Opium War from 1839 to 1842, however, the Qing dynasty had no choice but to grant major concessions. The British government forced China to open four new ports to foreign trade: Amoy (Xiamen), Foochow (Fuzhou), Ningpo (Ningbo), and Shanghai. British negotiators also insisted upon two privileges that would become hallmarks of Western imperialism in China. First, they demanded extraterritoriality, the right to subject British offenders to British rather than Chinese law. Second, they demanded most-favored-nation status, meaning that Britain would automatically benefit from concessions that China granted to any other country. In fact, as the historian Warren I. Cohen has observed, this demand for equal opportunity meshed well with Chinese calculations at the time. The imperial government, hoping to garner the goodwill of other Western powers to resist further British pressure, declared that all nations would have equal privileges in the treaty ports. "Now that the English barbarians have been allowed to trade," declared the Daoguang emperor, "whatever other countries there are, the United States and others, should naturally be permitted to trade without discrimination." In this way the United States, without firing a shot, came to enjoy the benefits that Britain had extracted through military intervention.

pretty sure they split up because of religious conflicts.

the answer to number 5 is fort sumter