You are given an elementary science question along with a few answer options. List all the words from the question that are essential and sufficient for choosing the correct answer option. Keep in mind that essential words are necessary to understand the meaning of the given question. However, non-essential words provide little information needed to select the correct answer. You can think about it like this: If the question was in another language, knowing the meaning of which words were necessary and enough for you to understand the question and answer it?. If your answer consists of multiple spans of words from the question, separate those using a comma (", "). Do not generate any word that is not present in the question. Make sure that your response is contained in the given question and the words are in the same order as the question.
 Grammatical correctness is not important.

Example Input: Question: All of these are ways to stay safe around electricity except (A) staying away from power lines. (B) using cords in good condition. (C) plugging many appliances into one outlet. (D) keeping electricity away from water.?
Example Output: safe, around, electricity, except

Example Input: Question: A decomposer is an organism that (A) hunts and eats animals(B) migrates for the winter(C) breaks down dead plants and animals(D) uses water and sunlight to make food?
Example Output: decomposer, organism

Example Input: Question: Which force causes rocks to roll downhill? (A) gravity(B) friction(C) erosion(D) magnetism?
Example Output:
force, causes, roll, downhill?