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'.

Example Input: Question: In humans, the *** process begins in  (A) the intestine, with squeezing. (B) the mouth, with chewing and saliva. (C) the stomach, with churning and acid. (D) the esophagus, with pushing towards the stomach.
Example Output: B.

Example Input: Question: Mount St. Helens is part of a volcanic chain that slowly formed on Earth where __________.  (A) continental plates collided (B) oceanic plates pulled apart (C) a continental and an oceanic plate pulled apart (D) a continental and an oceanic plate collide.
Example Output: D.

Example Input: Question: *** surface *** *** Moon *** made *** ***  (A) craters, highlands, and flat areas (B) swirling gases (C) large bodies of water (D) a mixture of gases and wate.
Example Output:
A.