Explanation
Correct answer: C.
Choice C is the best answer. “However” logically signals that the information in this sentence—that Hammurabi is mainly remembered for just a single achievement, the Code of Hammurabi—is contrary to what might be assumed from the previous information about Hammurabi’s many achievements.
Why the other choices are wrong
Choice A
Choice A is incorrect because “therefore” illogically signals that the information in this sentence is a result of the previous information about Hammurabi’s many achievements. Instead, this sentence makes a point that is contrary to what might be assumed from the previous information.
Choice B
Choice B is incorrect because “likewise” illogically signals that the information in this sentence is similar to the previous information about Hammurabi’s many achievements. Instead, this sentence makes a point that is contrary to what might be assumed from the previous information.
Choice D
Choice D is incorrect because “for instance” illogically signals that this sentence exemplifies the previous information about Hammurabi’s many achievements. Instead, this sentence makes a point that is contrary to what might be assumed from the previous information.