OE:
The underlined portion of the sentence contains the verbs appears and emitting, so check for parallel construction errors. The underlined portion of the sentence also contains the word where, so check whether it describes a location. The present tense verb appears is not parallel to the participle form emitting, so this is a parallel construction error. The word where describes the conclusion, which is not a place, so this is a where vs. which error. Eliminate choice A and look for any obvious repeaters. Choice E is an obvious repeater because it also uses where to describe the conclusion, so eliminate choice E. Now, evaluate the remaining answer choices individually, looking for reasons to eliminate each.
Choice B fixes both original errors but introduces a subject-verb agreement error since the plural subject holes does not agree with the singular verb emits, so eliminate choice B. Choice C fixes both original errors by removing where and replacing emitting with the present tense verb emits, and introduces no new errors, so keep choice C. For choice D, the verb having emitted is not parallel to appears, so eliminate choice D for a parallel construction error.
Choice A: No. The participle emitting is not parallel to appears. Where incorrectly refers to conclusion. Parallel Construction; Where vs. Which.
Choice B: No. The plural noun holes does not agree with the singular verb emits. Subject-Verb agreement.
Choice C: Correct.
Choice D: No. The verb having emitted is not parallel to appears. Parallel construction.
Choice E: No. Where incorrectly refers to conclusion. Where vs. Which.
The correct answer is choice C.