The correct answer is letter A.
Explanation: In the nineteenth and in the twentieth century most of people classified as middles class were living in tenement houses with bad conditions, but it was where they could live.
Mexico ceded to the United States Upper California and New Mexico. This was known as the Mexican Cession and included present-day Arizona and New Mexico and parts of Utah, Nevada, and Colorado.
A developing country might only have primary and secondary economic activities because the economy is not fully developed enough.
