What was the main response of the middle class to the challenges of city living?
a. escape to the suburbs
b. move to high rise apartments
c. rent out tenement buildings
d. attend vaudeville shows

The correct answer here is option A.

Explanation:

As the cities like New York and especially Los Angeles became more and more populated and dense they became a lot crowded and more dangerous. The people of middle class responded to these new challenges and diverse downtown residents by moving to the new suburbs that have been built. This middle class flight happened in droves.