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 Input:
Question: The systems of the human body work together. Which *** works with the *** *** by pulling on the *** to create ***?  (A) digestive (B) circulatory (C) muscular (D) nervou.

Ex Output:
E.


Ex Input:
Question: Which of the following *** would be *** as a *** *** of a ***?  (A) Shedding hair in the Spring (B) Ears perking up when someone approaches the front door (C) Falling asleep when tired (D) Bringing back a thrown Frisbe.

Ex Output:
E.


Ex Input:
Question: A student found a rock while hiking in the mountains. By looking at the rock, she could tell the  (A) exact weight of the rock. (B) length of time the rock had been on the hiking path. (C) color and shape of the rock. (D) exact length of the rock.

Ex Output:

C.