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.

Photosynthesis is the process that converts carbon dioxide and water into  
 (A) carbon and oxygen. (B) sugar and hydrogen. (C) sugar and oxygen. (D) nitrogen and carbon.
C

Which unit is used to indicate the amount of energy in food?  
 (A) ounce (B) degree (C) calorie (D) gram
C

A prairie dog living in a community barks loudly. Other prairie dogs nearby know that danger is near and quickly go underground to hide. Which sense are these prairie dogs using to communicate?  
 (A) hearing (B) smelling (C) tasting (D) touching

A