In this task, you need to answer basic science questions. For each question, several terms are intentionally masked with ***. This masking can cover very few or many of the question words. Clearly, if masked terms are important, the modified question will be impossible to answer. Please indicate the correct answer with one of the following responses: "A", "B", "C", "D" or "E". While "A"-"D" correspond to the answer options provided in the input, "E" represents "I don't know" for questions that do not provide enough information. Respond via "E" if the question is not answerable. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'.
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Question: Question: *** how *** does *** take to *** its *** *** the ***?  (A) one day (B) one month (C) one year (D) one centur.

Answer: E.


Question: Question: Which *** help to destroy pathogens such as bacteria that enter the human body?  (A) red blood cells (B) liver cells (C) white blood cells (D) brain cell.

Answer: C.


Question: Question: Which of the following activities is *** for the ***?  (A) recycling waste (B) conserving water (C) producing waste (D) reducing pollutio.

Answer:
E.