Why was the early West considered a "crossroads of culture"?

Question

Mexico originally owned the land, so the cultures of Americans, Mexicans, and Native Americans were all present in the West.
The California Gold Rush brought in people from all over the world, which resulted in cultural diffusion among the settlers there.**
California was known to accept many forms of religion and ethnicities, so people from different cultures migrated there to start new lives.
Those settlers who brought slaves with them to the West created cultural interactions between Native Americans, African Americans, and themselves.

Answer 1

and this is math how?

Answer 2

meant WH

Answer 3

I believe it is B

Answer 4

I agree with B.