First of all, this is a modifying phrase,
it will refer to the stuff that comes just after the comma.
Although damaged with bone infections, paleontologists -
no, paleontologists are not damaged with bone infections,
it has to be something like Big Al, you know. So, options
A and B can be accused of modifiers error, they can be eliminated.
Option D is kind of funny - because of this comma missing,
it tends to convey that dinosaur could be excavated by paleontologists
from the late Jurassic period. So, it's sounding as if these
scientists were from the Jurassic period, that's a funny meaning.
Now, it's between C and E. Now these are quite close answer
choices. I would say that the main problem is this sentence
reads better - although damaged with bone infection, Big Al, ..., could
be successfully excavated by paleontologists. In this one,
the paleontologist succeeded in excavating Big AL,
remove the stuff between two commas, Big Al, although damaged
with bone infections. So, what is damaged with bone infection
is not very clear because it comes very late in the sentence;
it becomes ambiguous
what is it referring to. So, C conveys the message more clearly,
C is a better choice.
