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.

Input: Consider Input: A delta can be seen from the air at the mouth of the Mississippi River. This delta was formed by  
 (A) erosion. (B) weathering. (C) conservation of soil. (D) deposition of sediment.

Output: D


Input: Consider Input: Which land feature is formed from erosion by waves?   
 (A) a sandbar (B) a sea cliff (C) a barrier reef (D) a barrier island

Output: B


Input: Consider Input: Scientists study the current conditions of many solar system objects to gain insight into conditions early in the history of Earth. Which phenomenon most closely models current theories of early Earth?  
 (A) liquid forming valleys on Mars (B) hundreds of active volcanoes on Io (C) rock and ice forming the core of Neptune (D) ice covering the entire surface of Europa


Output: B