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: When an octopus feels threatened, it can release black ink into the water. The ink MOST likely helps the octopus (A) move quickly through the water. (B) breathe oxygen from the water. (C) hide from predators. (D) use food faster.?
Example Output: octopus, release, black, ink, helps, octopus

Example Input: Question: Which gravitational pull has the greatest influence on Earth's tides? (A) the gravitational pull between Earth and the Moon (B) the gravitational pull between Earth and the Sun (C) the gravitational pull between Earth and Jupiter (D) the gravitational pull between Earth and Mars?
Example Output: gravitational, pull, greatest, influence, tides?

Example Input: Question: Which of the following is an adaptation to help an animal survive in a cold, snowy environment? (A) brown fur (B) migration (C) large eyes (D) hibernation?
Example Output:
adaptation, animal, survive