You are given a science question (hard-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.

[EX Q]: During which phase of meiosis does the separation of homologous chromosomes occur?  
 (A) prophase (B) anaphase (C) metaphase (D) telophase
[EX A]: B

[EX Q]: According to cell classification, prokaryotic cells are separated from eukaryotic cells. Which feature is often used to distinguish prokaryotic cells from eukaryotic cells?  
 (A) life processes (B) size differences (C) plasma membranes (D) energy molecules
[EX A]: B

[EX Q]: A species of bird has not been seen since the 1900s and is considered extinct. Which evidence would best disprove the claim that the bird is extinct?  
 (A) A bird watcher makes a sketch of the bird. (B) A scientist discovers fossil remains of the bird. (C) A researcher takes a photograph of the bird. (D) A park ranger finds a suitable habitat for the bird.
[EX A]:
C