Answer:
(2) paleontologists, or scientists...
Step-by-step explanation:
The best way to revise the given portion of the sentence is the second one. The name of scientists who use fossils to study prehistoric life forms is paleontologists, but the way the sentence was originally written is incorrect because that structure is not used in the English language. When we want to include an alternative name or define something, we should introduce the name/definition by the preposition or preceded by a comma:
So many fossils have been dug up in this otherwise unremarkable town that it has become a paradise for paleontologists, or scientists who use fossils to study prehistoric life forms.