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: 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.
Example Output: A

Example Input: Which property of air does a barometer measure?  
 (A) speed (B) pressure (C) humidity (D) temperature
Example Output: B

Example Input: A student walks to school each morning in Maine. It is dark outside when he begins walking. As the days pass, the student notices the mornings are becoming brighter. The Sun is rising earlier each day. He also notices that there is more daylight after school. The Sun is setting later in the day. Which change of seasons is occurring?  
 (A) winter to spring (B) summer to fall (C) spring to winter (D) fall to winter
Example Output:
A