Anil has noticed that infertility has been affecting many of his intergenerational friends and family. Based on this observation, Anil is writing his senior thesis on the effects that certain cities, water quality, and hormones might have on his friends. Anil will most likelyapproach his findings and paper using which theory?

A. Demographic transition theory
B. Cornucopian theory
C. Zero population growth theory
D. Malthusian theory