This question is focused on the understanding of English grammar structures. The correct answer is 'C. Conditional Sentences' because they are used to express wishes or hypothetical situations. Option A is incorrect because the Future Tense is used for actions that will happen in the future. Option B is incorrect because the Past Perfect Tense is used for actions that were completed before another past action. Option D is incorrect because the Present Perfect Tense is used for past actions with present relevance.