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.

[EX Q]: Sara tums on a flashlight and holds an object up to the light. How will she be able to tell if the object is opaque?  
 (A) No light will shine through. (B) Some light will be reflected. (C) The light will bend at an angle. (D) Light will shine clearly through.
[EX A]: A

[EX Q]: Molly was making iced tea by putting tea bags in boiling water. She needed to cool the hot tea quickly, so she poured it into a pitcher full of ice. Which best describes the flow of thermal energy?  
 (A) from the ice to the tea (B) from the tea to the ice (C) from the pitcher to the tea (D) from the ice to the pitcher
[EX A]: B

[EX Q]: Sediments are generally classified by particle size. A student would like to classify sediments by their source. Which statement best describes this alternate classification?  
 (A) acceptable if the sediments are also identified by particle size (B) acceptable if the factors used for the classification are given (C) unacceptable because others would not understand the classification system (D) unacceptable because this is not the way scientists usually classify sediments
[EX A]:
B