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: *** *** *** *** *** *** explains *** *** tilt *** Earth *** *** axis causes summer *** *** warmer *** winter *** *** Northern Hemisphere?  (A) The warm ocean currents flow from the tropics to the Northern Hemisphere in the summer. (B) The rays of the Sun strike the Northern Hemisphere more directly in the summer. (C) The greenhouse effect increases in the Northern Hemisphere in the summer. (D) The Northern Hemisphere is closer to the Sun in the summer.
[EX A]: B.

[EX Q]: Question: *** known living things are made up of ___.  (A) eggs (B) cells (C) cell walls (D) gelati.
[EX A]: B.

[EX Q]: Question: *** *** can best *** the *** of *** in *** by  (A) converting deforested areas into malls. (B) planting trees to replace what they cut down. (C) adding pesticides to the soil around the trees. (D) removing the tree stumps when trees are cut down.
[EX A]:
E.