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.

Carlos was playing on a slide on a sunny summer day. Which property of the slide tells Carlos how much energy the slide absorbed from the Sun?  
 (A) the mass (B) the color (C) the height (D) the temperature
D

In 1971, the bones of an extinct flying dinosaur were discovered. This kind of discovery helps everyone learn more about  
 (A) impact of humans on Earth. (B) effect of gravity on animals. (C) history of animal species on Earth. (D) likelihood that dinosaurs will reappear.
C

Rheumatoid arthritis is an autoimmune disease that affects the joints. Which of these events causes the symptoms of this disease?  
 (A) The body's immune system attacks specific tissues. (B) The cells of the immune system begin to grow rapidly. (C) The body's immune system fails to fight off infections. (D) The cells of the immune system are absorbed by antigens.

A