The black‐footed ferret was listed as endangered in the United States in the late 1960s. In the 1970s, it was thought that the species was extinct. However, a small population was discovered in Wyoming, in 1981. However, this remaining population dwindled to 18 individuals when an outbreak of sylvatic plague and canine distemper affected the black footed ferret. What phenomenon is demonstrated in this case study? A) A population mutation that cause susceptibility to disease. B) A population bottleneck that decreased genetic variation in the ferret population. C) Artificial selection, as humans captively bred only the strongest individuals to survive and reproduce. D) A gene flow from the surviving population to other members of the species that increased genetic variation.