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 Q]: Why does the leaf of a plant look green?  
 (A) Because it absorbs green light (B) Because it reflects green light (C) Because it absorbs only yellow and blue light (D) Because it reflects a mixture of yellow and blue light
[EX A]: B

[EX Q]: Researchers are developing new types of crop plants with desirable characteristics such as disease resistance and drought tolerance. Crossing plants so that the next generation will express desirable traits is best described as  
 (A) selective breeding. (B) natural selection. (C) genetic engineering. (D) gene sequencing.
[EX A]: A

[EX Q]: Ella has several wooden blocks. When Ella holds the blocks in her hand, she feels that they are rough. Which term best describes what Ella feels?  
 (A) a prediction (B) a conclusion (C) a hypothesis (D) an observation
[EX A]:
D