Please answer the question based on the following passage. You need to choose one letter from the given options, A, B, C, or D, as the final answer, and provide an explanation for your choice. Your output format should be ###Answer: [your answer] ###Explanation: [your explanation]. ###Passage:The concepts of physics are usually very standardized and rigorous.The physical quantities represented by physics terms have clear definitions, measurement methods and conversion relationships.For dark energy, physicists and cosmologists still know nothing about it."Dark energy" refers to the most profound problem in current cosmology. ###Question:Which of the following statements is most appropriate to continue the above as its conclusion? ###Options: (A)"Dark energy" is obviously not a clear physics concept. (B)Scientists use "dark energy" to name a cosmic puzzle is helpless. (C)"Dark energy" refers to the confusing phenomenon that the previously discovered universe is accelerating expansion. (D)Scientists still do not know the deep connotation behind the term "dark energy". Give two different versions of responses. Please separate the responses with 6 asterisk symbols: ******.
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