Final answer:
George Perkins Marsh is associated with the early stages of the conservation movement, specifically due to his critical work on the environmental impact of deforestation.
Step-by-step explanation:
The question pertains to George Perkins Marsh and his contribution to the beginning of concern in a particular area. Given the historical context provided, Marsh was instrumental in the early stages of the conservation movement. His book, Man and Nature, published in 1864, critically examined the depletion of forests near his home and was influential in raising awareness about the environmental impact of deforestation. Therefore, the most appropriate answer to the student's question is A) Conservation, reflecting Marsh's significant role in the early conservation efforts which laid the groundwork for later environmental policies and preservation activities.