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 Input:
A main function of a plant's seed is to  
 (A) store food to be used during early development (B) attract pollen to be used during development (C) take in light energy to be used during photosynthesis (D) produce chlorophyll to be used during photosynthesis

Ex Output:
A


Ex Input:
Which phrase does not describe asexual reproduction in organisms?  
 (A) requires two parents (B) little variation in offspring (C) only one type of cell involved (D) duplicates its genetic material

Ex Output:
A


Ex Input:
Of these research projects, which is the best choice for a student who is interested in environmental issues to study?  
 (A) making cars run on less fuel (B) finding more sites for copper mines (C) making ocean liners bigger and faster (D) replacing human workers with robots

Ex Output:

A