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 population of plants growing on an island consisted of two varieties, one with thorns and the other without. Over a period of many years, the variety with thorns gradually disappeared. Which process most likely brought about this change in the plant population?  
 (A) gene flow (B) genetic drift (C) natural selection (D) random mutation

Output: C


Input: Consider Input: What has occurred when bubbles form in a liquid that is being heated?  
 (A) Oxygen is absorbed from the air. (B) Heat is radiating in the liquid. (C) The boiling point has been reached. (D) Molecular stability in the liquid is increasing.

Output: C


Input: Consider Input: Joel made some measurements and recorded this data: Sample 1 - 45 mL Sample 2 - 15 mL Sample 3 - 30 mL Sample 4 - 20 mL Which of these tools would most likely have been used to obtain these measurements?  
 (A) test tube (B) meter stick (C) spring scale (D) graduated cylinder


Output: D