One of the Reasons Parks and Outdoor Recreation Became Popular

One of the reasons parks and outdoor recreation became popular in the late nineteenth century was because:

A) of the vast amount of open space that was available in the cities
B) of the ideals of social Darwinism
C) most tenement buildings were constructed next to large parks
D) concerns over congestion and disease led many to seek ways to restore their vitality and improve their health
E) it was a way to escape the immigrant population in the city