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:No notochords are catheter animals, and all pterosaurs are catheter animals.Therefore, no pterosaurs belong to the great ape family. ###Question:Which of the following statements must be assumed in the above reasoning? ###Options: (A)All great apes are catheter animals. (B)All great apes are notochords. (C)No great apes are notochords. (D)No notochord is pterosaur.