According to the map on page 251 of your textbook, which of the following states or territories listed below contained the most silver mining regions

A. Montana

B. Nevada

C. Dakota

D. California

It would be easier to answer if i could see the grafic from your textbook, but here is some information, hopefully useful:

A. Montana

historically the second largest producer of silver

B. Nevada

-currently the second largest producer of silver - after Alaska

I think that I would go with this answer - was also home to the Comstock Lode, Tonapah and Eureka silver mining districts.

D. California

-has a number of silver mines