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: Spring tides occur during which lunar phases?  
 (A) first quarter and last quarter (B) full moon and new moon (C) when the moon is waxing (D) when the moon is waning
Example Output: B

Example Input: After a star runs out of most of its hydrogen fuel, it becomes hotter and more luminous. What stage does this represent in the life cycle of a star?  
 (A) quasar (B) protostar (C) red giant (D) white dwarf
Example Output: C

Example Input: Scientists often work together to solve a problem. Sometimes they work in laboratories. Sometimes they are outside doing fieldwork. The chart provides a list of some careers in science. Which scientists might work together to save a polluted wetland?  
 (A) chemist, botanist and ecologist (B) astronomer, ecologist and physicist (C) physicist, paleontologist and chemist (D) botanist, astronomer and paleontologist
Example Output:
A