Answer:
More factory goods than cotton being sold to other countries was a sign that life was improving in the North.
Explanation:
A is correct because this means that the North became industrialized, and instead of being dependent on manufactured goods from other countries, it became a manufacturing hotspot, meaning the economy was booming and the life of the people was improving.
B is not correct because problems of any sort, let alone cultural one, would lead to any prosperity.
C is not correct because it was not the rich families that were increasing in number but it was the formation of the middle class.
D is not correct because the communication and transportation means can be present in areas that are stagnating or where the majority of the people have bad lives, so they are not a good indicator.