Immigration, American Policy, and Foreign Policy.
the industrialization of the northeast made it possible for women to work in factories.
I believe the correct answer is B.
Answer: No other European power had established a presence in the area.
In the early 19th century, Russia had already established some colonies in Alaska, securing its presence in America. Russia was expanding East, across Siberia, and eventually started moving south, until it reached Northern California.
Americans who were involved in the sea otter business proposed some joint hunting expeditions with Russian supervisors and Native Alaskan hunters to hunt seals along the Californian coast. These expeditions allowed the Russian parties to observe large stretches of uncolonized land. This led to the conclusion that a Russian settlement could be established in California.
These advances in the history of technology stimulated societies to adopt new ways of living and governance.