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.

About how long is a lunar cycle?  
 (A) 1 day (B) 1 week (C) 28 days (D) 52 weeks
C

A student placed a small chip of limestone into a hydrochloric acid solution, and carbon dioxide gas was released. The carbon dioxide provided evidence that   
 (A) only a physical change occurred. (B) a chemical change occurred. (C) only a loss of mass occurred. (D) the formation of an element occurred.
B

What process in the atmosphere protects people from the ultraviolet rays in sunlight?  
 (A) Ozone absorbs ultraviolet light. (B) Nitrogen reflects ultraviolet light. (C) Water vapor scatters ultraviolet light. (D) Carbon dioxide blocks ultraviolet light.

A