The population of _________ exploded from 1,000 before the Gold Rush to 50,000 by 1856. A. Los Angeles B. San Francisco C. San Diego D. Sacramento

B. San Francisco

The population of San Francisco exploded from 1,000 before the Gold Rush to 50,000 by 1856. This rapid population growth was primarily due to the California Gold Rush, which started in 1848 when gold was discovered at Sutter's Mill in Coloma, California.

Extra: The California Gold Rush was a seminal event in American history that led to a large migration of people to California from all over the United States and other parts of the world. People who came to seek their fortunes in gold mining were nicknamed "Forty-Niners," referencing the year the Gold Rush peaked, 1849. San Francisco, in particular, became a booming metropolis as it served as a primary port and gateway to the goldfields. The city developed a variety of businesses and services to accommodate the needs of the influx of miners and their families. This period was marked by rapid development, the establishment of infrastructure, and significant cultural change due to the diverse backgrounds of the people who came to California during the Gold Rush.