instruction:
You are given a science question (hard-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.
question:
Which element makes up most of the air we breathe.  
 (A) carbon (B) nitrogen (C) oxygen (D) argon
answer:
B


question:
Which of these will result in the least gravitational attraction?  
 (A) two 2g objects 2 meters apart (B) two 2g objects 4 meters apart (C) two 1g objects 6 meters apart (D) two 1g objects 8 meters apart
answer:
D


question:
The Steller sea lion population has been decreasing in parts of Alaska. New evidence suggests that Steller sea lions need herring as a part of their diet in order to survive. Pollock, another type of fish, also feed on herring. Which would most likely help the Steller sea lion population to increase?  
 (A) increasing the number of pollock (B) changing the diet of the sea lions (C) improving the habitats of herring (D) changing the location of the sea lions
answer:

C