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.

Which particle type can be identified as being from a specific element?  
 (A) electron (B) atom (C) neutron (D) proton
B

The fusion reaction that fuels the Sun converts hydrogen into  
 (A) carbon. (B) iron. (C) neon. (D) helium.
D

Which process directly adds carbon into the atmosphere?  
 (A) increasing plant populations (B) decreasing animal populations (C) burning fossil fuels (D) forming sedimentary rock

C