Answer:
c. More individuals died per year than before 2010.
Step-by-step explanation:
The reason is very simple. The black footed ferret specie preys specifically on prairie dogs and it was considered there best primary prey for black-footed ferrets in the environment. But then the unexpected thing happen, the prairie dog species contracted a highly lethal sylvatic plague that is caused by a bacteria that effect these species. As a result of the plague the number of preys begin to decrease year by year and as a result there was noticed a gradual decline in the population of black-footed ferrets because more individuals died per year than before 2010.