A college student spent the week hiking on the Appalachian Trail and he saw only one other hiker the entire time. Now he is walking in New York City's Times Square on a Friday night. The streets are packed with people and the skyscrapers are lit by thousands of lights. In which environment are humans having a significant impact and why?

A)in New York City because the population density of humans is very high compared with other visible types of life
B)in New York City because of the scarcity of the natural environment compared to man-made structures
C)in both New York City and on the Appalachian Trail because the student was present in both places and thus impacted the environment
D)in both New York City and on the Appalachian Trail because the large ecological footprint of humans affects the entire planet
E)in both New York City and on the Appalachian Trail because, at some point in history, both areas have been inhabited by humans