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.

Example Input: Which of the following is most likely to disrupt the natural balance in an ecosystem?  
 (A) introduction of a non-native species (B) reduced daylight hours during winter (C) preventing the cutting of trees in forests (D) riverbank erosion resulting from springtime flooding
Example Output: A

Example Input: When would the highest tides occur along the Texas coast?  
 (A) at sunrise (B) at sunset (C) during a full moon (D) during a half moon
Example Output: C

Example Input: The surface of Earth is covered mostly by  
 (A) solid rock (B) molten rock (C) ice (D) water
Example Output:
D