How did Joanne Nagel explain the increase in the number of people identifying themselves as "American Indian" when birth rates stayed the same?

A) Legal changes has made it harder for American Indians to vote.
B) The development of the "Red Power" movement has shifted negative stereotypes of Indians.
C) Urbanization has made it harder for people to find other people of American Indian heritage.
D) American Indians have migrated to the United States from Canada at high rates.

Answer: B