TASK DEFINITION: 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'.
PROBLEM: Question: Which example best shows *** that make up the *** *** in the *** ***?  (A) heart, blood, vessels (B) nose, trachea, lungs (C) brain, spinal cord, nerves (D) esophagus, stomach, intestine.

SOLUTION: E.

PROBLEM: Question: A student riding a *** observes that it *** *** on a *** road than on a rough road. This happens because the *** road has  (A) less gravity (B) more gravity (C) less friction (D) more frictio.

SOLUTION: E.

PROBLEM: Question: In *** ***, the *** *** ___.  (A) one rotation on its axis (B) one rotation around the Sun (C) one orbit around Mars (D) one revolution around the Moo.

SOLUTION:
E.