Explanation
Correct answer: D.
Choice D is the best answer. "Finally" logically signals that the actions in this sentence—the removal, cataloging, and analysis of artifacts—are the next and final steps in a process, following the previous actions of surveying, digging, recording, and mapping.
Why the other choices are wrong
Choice A
Choice A is incorrect because "for instance" illogically signals that the actions in this sentence are an example of the actions in the previous sentence. Instead, the removal, cataloging, and analysis of artifacts are the next and final steps in a process.
Choice B
Choice B is incorrect because "on the contrary" illogically signals that the actions in this sentence are directly opposed to the actions in the previous sentence. Instead, the removal, cataloging, and analysis of artifacts are the next and final steps in a process.
Choice C
Choice C is incorrect because "earlier" illogically signals that the actions in this sentence occur before the actions in the previous sentence. Instead, the removal, cataloging, and analysis of artifacts are the next and final steps in a process.