Explanation
The correct option to complete the sentence is:
A) had answered
Explanation: The correct sentence would be "If I had answered one more question, I would have passed." This sentence follows the third conditional structure, which expresses a hypothetical situation in the past. The verb form "had answered" is the correct form for the past perfect tense, indicating an action completed before another past action. Option B) would have answered is incorrect because it uses the wrong verb tense. Option C) would answer is incorrect because it uses the present conditional tense, which does not fit the past hypothetical situation described. Option D) answered is incorrect because it does not convey the hypothetical nature of the situation.