TASK DEFINITION: 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.
PROBLEM: An enclosed 20 mL metal cylinder was filled with a gas sample at room temperature. The sample then was transferred to an empty 40 mL enclosed container, also at room temperature. After being transferred, the volume of the gas was  
 (A) 10 mL. (B) 20 mL. (C) 30 mL. (D) 40 mL.

SOLUTION: D

PROBLEM: A girl found the skull of an animal. She did not know what the animal was but she was sure that it preyed on other animals for its food. What clue led to this conclusion?  
 (A) The eye sockets faced sideways. (B) The skull was much longer than it was wide. (C) There was a projecting ridge along the top of the skull. (D) Four of the teeth were long and pointed. (E) The jaws could move sideways as well as up and down.

SOLUTION: D

PROBLEM: Which objects are the most useful for collecting data on the speed of a toy car?  
 (A) microscope, computer, ruler (B) thermometer, calculator, magnet (C) stopwatch, calculator, meter stick (D) camera, digital recorder, safety goggles

SOLUTION:
C