You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Input: Consider Input: Which best demonstrates that waves transfer energy?  
 (A) a bell ringing in a tower (B) a leaf falling from a tree (C) a ball rolling down a hill (D) a flag moving in the wind

Output: A


Input: Consider Input: Ice will form on small ponds when the temperature drops below 0°C. Which property of ice is most beneficial to fish living in these ponds?  
 (A) Ice has a temperature colder than the temperature of water. (B) Ice absorbs sunlight that is reflected by water. (C) Ice traps more pollution than is trapped by water. (D) Ice had a density lower than the density of water.

Output: D


Input: Consider Input: Sea stars are consumers that live in a tide pool ecosystem that is alternately submerged and exposed by tides. This type of ecosystem contains poisonous anemones and many species of shellfish. The sea star's advantage in this ecosystem is that it can  
 (A) pry open shells. (B) produce a tiny light. (C) move quickly along the sea bottom. (D) survive the pressurized atmosphere of deep water.


Output: A