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'.

[EX Q]: Question: Approximately how long does *** take to *** its *** around the ***?  (A) one day (B) one month (C) one year (D) one centur.
[EX A]: E.

[EX Q]: Question: *** *** *** *** *** *** ****** *** *** *** *** *** *** ***d?  (A) In a dry area (B) In a dark room (C) On a plant stand (D) Near a sunny plac.
[EX A]: E.

[EX Q]: Question: A *** on top of a *** is *** at 30 *** *** in 1957. *** years later, in 2007, the *** is *** again and is now 21 *** high. What *** best *** the *** for the rock's *** in ***?  (A) weathering (B) wind erosion (C) water erosion (D) chemical erosio.
[EX A]:
E.