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.

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
A

Which describes a material that is not a food?  
 (A) It stores energy but not nutrients. (B) It does not store energy or nutrients. (C) It stores energy and nutrients. (D) It does not store energy but stores nutrients.
B

Which of the following makes up the smallest region in the electromagnetic spectrum?  
 (A) radio waves (B) infrared light (C) visible light (D) gamma rays

C