The Fact That Infection by Bd Causes Lethargy in Many

The fact that infection by Bd causes lethargy in many infected amphibians can have what effect on efforts to accurately census the numbers of dead or dying amphibians at a particular time, in a particular habitat?

A) It can cause underestimation, due to infected amphibians preferring to seek out refuges relative to uninfected amphibians.
B) It can cause underestimation, due to increased predation on, and removal of, infected amphibians relative to uninfected amphibians.
C) It can cause overestimation, because infected frogs should be more readily observable to human census-takers than should uninfected amphibians.
D) All three of the above statements are plausible.
E) Two of the above statements are plausible.