TASK DEFINITION: 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.
PROBLEM: Many horses grow a heavy coat in autumn and shed that coat in spring. Scientists were not sure if temperature or the amount of daylight per day (called the photoperiod) caused the change. So, they conducted an experiment and concluded that the change in photoperiod was responsible for the biological changes. Shedding caused by which set of conditions would have helped them arrive at this conclusion?  
 (A) a constant photoperiod, but varied temperatures (B) a varied photoperiod, and varied temperatures (C) a constant photoperiod, and a constant temperature (D) a varied photoperiod, but a constant temperature

SOLUTION: D

PROBLEM: A pharmaceutical company developed a drug to help relieve headaches. Recently, the pharmaceutical company discovered that the drug may cause nausea in a small number of people who might take the drug. Which is the most ethical course of action that the drug company could take?  
 (A) Discontinue the use of the drug. (B) Inform people of the possible side effects. (C) Reduce the amount of drug given to people. (D) Modify the drug to include medicine that prevents nausea.

SOLUTION: B

PROBLEM: An athlete can run 9 kilometers in 1 hour. If the athlete runs at that same average speed for 30 minutes, how far will the athlete travel?      
 (A) 18 kilometers (B) 9 kilometers (C) 4.5 kilometers (D) 3.3 kilometers

SOLUTION:
C