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'.

Question: *** *** *** tiger get stripes?  (A) from its environment (B) from its food (C) from its offspring (D) from its parent.
D.

Question: *** safely conduct *** experiment *** chemicals*** *** *** *** always ***?  (A) Work in large groups. (B) Wear safety goggles. (C) Wear short sleeves. (D) Keep a window open.
B.

Question: When a substance undergoes a change and a new substance is formed with different physical and chemical ***, the change is called ___.  (A) nuclear (B) chemical (C) reversible (D) physica.

B.