Archaeologist: The latest discovery at the dig site at Water Creek is

Archaeologist: The latest discovery at the dig site at Water Creek is a large bone. The bone appears to be the tibia, or shin bone, of a hominid species. Because of the condition of the soil and extensive contamination, radiometric dating has been able to place the bone's age within a range of 1.5 and 2 million years. However, the bone shows signs of damage associated with the mammoth plague, which ran rampant in this part of the world from 1.9 to 2 million years ago. Thus, we can further pinpoint the age of the bone within a range of one hundred thousand years.

Radiometric dating : bone's age 1.5 and 2 million years
Bone signs : bone's age 1.9 and 2 million years
Conclusion: Bone has a range of 1.9 to 2 million years old

But what if multiple plagues (and not just one) took place between 1.5 and 2 million years ago? - This can be a weakener

Which of the following, if true, casts the most doubt on the archaeologist's suggested range of the age of the bone?

a. Most other animal fossils uncovered in the area surrounding the dig site have been found by carbon-dating to be more than 2 million years old.Other animal fossils? unrelated. We are concerned about that particular bone
b. The mammoth plague killed mammoths and other large animals but not hominids. This can be a close option, but the argument says damage. Even if the mommonths were not killed, thier boned could have been damaged. Thus, if bones show signs of plague, bones can be dated suitably. Thus not a weakener
c. Ample archaeological evidence exists to support the hypothesis that the last outbreak of mammoth plague occurred 1.9 million years ago.Author is agreeing to this fact. Thi does not weaken the conclusion
d. Fossils from the area that are between 1.5 and 1.8 million years old provide evidence of the mammoth plague.
e. Fossils from the area that are more than 2 million years old provide evidence of the mammoth plague.More than 2 million has no effect on the conclusion. We need something between 1.5 and 2 years. Just as option D states, if the plague happened between 1.5 and 1.8 million years ago also, the it is unlikely that bone is from a hominid that existed 1.9 to 2 million years ago