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.

Input: Consider Input: A human CANNOT survive the loss of which of the following?
(A) The appendix (B) The liver (C) A lung (D) A kidney

Output: B

Input: Consider Input: While collecting wildflowers, a student begins to sneeze and has itchy, watery eyes. What bodily system causes this reaction?
(A) immune (B) nervous (C) muscular (D) circulatory

Output: A

Input: Consider Input: Which pair of elements has the most similar properties?
(A) Li and B (B) I and Ca (C) K and He (D) N and P
Output: D