The graph shows how a Serengeti Buffalo population changed over a period of years. At the beginning of the time period, the buffalo were affected by the Rinderpest virus, a debilitating disease with a high mortality rate. However, within five years, the virus was eliminated. After Rinderpest was eliminated, what was the ecosystem's carrying capacity for buffalo, based on the graph?
A. 35,000 buffalo
B. 55,000 buffalo
C. 60,000 buffalo
D. 65,000 buffalo