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]: Most of the United States is a part of which tectonic plate?  
 (A) Pacific Plate (B) Eurasian Plate (C) North American Plate (D) South American Plate
[EX A]: C

[EX Q]: The Piedmont and Coastal Plains regions in Maryland produce crops such as corn, soybeans, wheat, tobacco, tomatoes, and apples. Which environmental factor most likely influences which crops are grown in these regions?  
 (A) soil quality (B) wind speeds (C) bird migration (D) water temperature
[EX A]: A

[EX Q]: Which process has most likely occurred when new traits appear in a species?  
 (A) selective breeding (B) genetic mutation (C) crossbreeding (D) cloning
[EX A]:
B