For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes 4 to 5 days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100 percent; other species seem able to survive the infection. What makes it risky to rely on the presence of chitin in adult amphibian skin as the sole positive test for the presence of chytrids?

a. Other mycoses may be in progress in the same amphibian simultaneously.
b. Bacterial infections may be simultaneously underway in the amphibian.
c. The amphibian may harbor arthropod ectoparasites simultaneously.
d. Three of the responses above are correct.
e. Two of the responses above are correct.