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 of the following has the least momentum?  
 (A) a 0.5 kg mass with a 1000 m/s velocity (B) a 1 kg mass with a 100 m/s velocity (C) a 10 kg mass with an 11 m/s velocity (D) a 100 kg mass with a 2 m/s velocity

Answer: B


Question: Some bacteria use iron found in their systems as a means to guide their movement. Which stimulus most likely triggers this movement mechanism?  
 (A) magnetism (B) oxygen (C) light (D) heat

Answer: A


Question: What is the complementary base to cytosine in DNA?  
 (A) uracil (B) thymine (C) guanine (D) adenine

Answer:
C