OG详解-OG9 文法 Q4

Choice C is the best answer. The convention being tested is punctuation use between a main clause and two supplementary elements. In this choice, the commas after “nickname” and “however” are correctly used to separate the supplementary adverb “however” from the main clause (“Scott-Heron… nickname”) on one side and the supplementary participial phrase (“feeling…bluesologist”) on the other. 
Choice A is incorrect because it fails to mark the boundary between the supplementary adverb “however” and the supplementary phrase (“feeling…bluesologist”). Choice B is incorrect because a semicolon can’t be used in this way to join the supplementary adverb “however” and the supplementary phrase (“feeling…bluesologist”). Choice D is incorrect because a semicolon can’t be used in this way to join the main clause (“Scott-Heron…nickname”) and the supplementary word and phrase (“however” and “feeling…bluesologist”). Moreover, placing the semicolon after “nickname” illogically signals that the following information (Scott-Heron’s feeling that the nickname didn’t encapsulate his devotion to the blues tradition) is contrary to the information in the previous clause (Scott-Heron’s resistance to the nickname).