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.

[Q]: After a star runs out of most of its hydrogen fuel, it becomes hotter and more luminous. What stage does this represent in the life cycle of a star?  
 (A) quasar (B) protostar (C) red giant (D) white dwarf
[A]: C


[Q]: Which best describes a scientific theory?  
 (A) It is still being tested. (B) It is true, once written. (C) It is different for each continent. (D) It is determined in a court of law.
[A]: A


[Q]: As global temperatures increase, certain organisms will be more affected than others. The changes associated with global warming may result in an increase in sea level. Which organisms will be affected most as a result of the change in sea level?  
 (A) birds that eat fish from shallow waters (B) fish that live in coral reefs in shallow waters (C) mammals that swim in cold, deep ocean waters (D) crustaceans at the bottom of deep sea ocean waters
[A]:
B