Explanation
Correct answer: D.
Choice D is the best answer. “Finally” logically signals that the information in this sentence—that the artisan slips paper in and out of the liquid to transfer the design onto paper—is the final step in the process of Turkish paper marbling, which began with what happens “first” (filling a tray with a solution) and continued with what happens “next” (adding inks or paints to the solution).
Why the other choices are wrong
Choice A
Choice A is incorrect because “actually” illogically signals that the information in this sentence about slipping paper in and out of liquid to transfer a design onto paper is unexpected in light of the previously described steps. Instead, the sentence describes the final step in the process of Turkish paper marbling.
Choice B
Choice B is incorrect because “therefore” illogically signals that the information in this sentence about slipping paper in and out of liquid to transfer a design onto paper is a consequence of the previously described steps. Instead, the sentence describes the final step in the process of Turkish paper marbling.
Choice C
Choice C is incorrect because “nevertheless” illogically signals that the information in this sentence about slipping paper in and out of liquid to transfer a design onto paper contrasts with the previously described steps. Instead, the sentence describes the final step in the process of Turkish paper marbling.