You are given a science question (easy-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.

Ex Input:
Which of the following best describes a role of mushrooms in ecosystems?  
 (A) capturing energy from sunlight (B) consuming living plant material (C) taking energy from animal hosts (D) breaking down dead plant material

Ex Output:
D


Ex Input:
A girl found the skull of an animal. She did not know what the animal was but she was sure that it preyed on other animals for its food. What clue led to this conclusion?  
 (A) The eye sockets faced sideways. (B) The skull was much longer than it was wide. (C) There was a projecting ridge along the top of the skull. (D) Four of the teeth were long and pointed. (E) The jaws could move sideways as well as up and down.

Ex Output:
D


Ex Input:
Ethanol is a type of alcohol made from plants. Sugarcane and corn, which are both used in foods such as cereals and breads, are used to make ethanol. Burning ethanol provides a clean source of energy because the products of ethanol are water and carbon dioxide. Therefore, mixing ethanol with gasoline reduces harmful waste products. In the 1970s, many Brazilians drove cars with engines that used an ethanol gasoline mixture. This alternative fuel conserved the limited supply of gasoline available at that time. In the 1990s, gasoline became cheaper than ethanol, and Brazilians returned to driving more gasoline-fueled cars. Recently, Brazilians started driving more cars that use an ethanol-gasoline mixture. Ethanol is a good alternative fuel because it  
 (A) reduces air pollution (B) increases biodiversity (C) reduces sound pollution (D) increases ozone emissions

Ex Output:

A