How did the Voting Rights Act of 1965 change the demographics of the two major American political
parties?

More African-American joined the Democratic Party while the Republican Party lost a lot of white supporters in the South.

Explanation:

After the passage of the Voting Rights of 1965 by President Johnson, there was a significant increase in the number of minority  and African-Americans voters.The newly registered African-American voters inclined more towards the Democratic Party leading to a massive increase in its supporters. On the other hand, the Republican lost a lot of white supporters in the South.This was mainly because of the adoption of Richard Nixon's “Southern strategy” by the Republican Party.

Ibelieve the correct answer is d.