instruction:
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.
question:
Which of the following properties best describes a material's ability to resist scratching?  
 (A) weight (B) flexibility (C) length (D) hardness
answer:
D


question:
Which of these animals has a young form that looks the most like the adult form?  
 (A) moth (B) human (C) frog (D) butterfly
answer:
B


question:
What is the primary function of macrophages?  
 (A) absorb oxygen and transfer it to body cells (B) consume pathogens and assist the immune system (C) accumulate at an injury and initiate the clotting process (D) contain metabolites and maintain a balance of fluids
answer:

B