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: How do plants most commonly break large rocks into smaller pieces?  (A) Plant leaves insulate surrounding rocks from extreme temperatures. (B) Plant roots grow into cracks in rocks. (C) Seeds from plants fall onto rocks and release acidic compounds. (D) Stems of plants surround and squeeze rocks.
[EX A]: B.

[EX Q]: Question: Tobias rode his *** on a *** for a *** *** ***. On average, he passed a 1 *** marker every 3 *** during this ***. Which of the following was his *** *** for this *** *** ***?  (A) 10 km/hr (B) 15 km/hr (C) 20 km/hr (D) 25 km/h.
[EX A]: E.

[EX Q]: Question: In which *** in *** *** *** is the *** period of ***?  (A) June (B) April (C) December (D) Octobe.
[EX A]:
E.