The correct answer is A. Because of the Gold Rush attracting settlers all over the world California population diverse.
Explanation
Gold Rush was a phenomenon that occurred in the United States, specifically in California from 1847 to 1855 when the gold mining was booming, causing the arrival of people from other parts of the United States and other continents like Europe, Asia, and Australia. That phenomenon caused the expansion of many buildings and services, and a government system in San Francisco, that allowed California to become a State of the Union in 1950. So, the correct answer is A. Because of the Gold Rush attracting settlers all over the world California population diverse.