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.

Ex Input:
Question: Which of the following represents a chemical reaction? (A) a sugar cube dissolving in water. (B) ice cubes forming in a freezer. (C) ice cream melting in a bowl. (D) a cake baking in an oven.?

Ex Output:
chemical, reaction?


Ex Input:
Question: Mr. Burk's students test the ability of aluminum, plastic, and sand to conduct electricity. Which could be a reasonable entry in their scientific journals after testing the three materials? (A) Only aluminum conducts electricity. (B) Aluminum, plastic, and sand are good conductors. (C) Only plastic and sand conduct electricity. (D) Only sand conducts electricity.?

Ex Output:
ability, sand, conduct, electricity., reasonable, entry, scientific, journals


Ex Input:
Question: Summers in New York State can be very hot and humid, causing people to turn up their air conditioners to cool their homes. What is one way energy can be conserved? (A) Open the windows. (B) Turn the thermostat up to a higher temperature. (C) Drink more water. (D) Turn the thermostat down to a lower temperature.?

Ex Output:

hot, air, conditioners, energy, conserved?