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.

[EX Q]: Many things can contribute to the development of a theory. A student made a list of some things that might help scientists develop a theory. Observations Calculations Conversations Publications From the student's list, which must be used in the development of every theory?  
 (A) Observations (B) Conversations (C) Publications and calculations (D) Calculations and conversations
[EX A]: A

[EX Q]: A student has just completed a laboratory activity. What is the last action that the student should perform before leaving the lab area?  
 (A) wash hands (B) turn off all equipment (C) put away all glassware (D) wash instruments and table tops
[EX A]: A

[EX Q]: A black brick exposed to sunlight becomes warm. How is energy from the Sun transferred to the brick?  
 (A) convection (B) conduction (C) radiation (D) reflection
[EX A]:
C