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 student plants rosebushes in her front yard. The student is frequently seen pulling weeds from the base of the rosebushes. What is the most likely reason that the weeds are pulled?  
 (A) Weeds add fertilizer to the soil. (B) Weeds use nutrients the roses need to grow. (C) Weeds increase the bacteria in the soil. (D) Weeds consume most of the oxygen.

Ex Output:
B


Ex Input:
A DNA strand contains codons, which consist of a sequence of three nucleotides. Which best describes the importance of codons found in the sequence of DNA?  
 (A) They contain the code for messenger RNA. (B) They signal the start of mitotic cell division. (C) They ensure proper replication of the genetic code. (D) They are used to assemble amino acids for protein synthesis.

Ex Output:
D


Ex Input:
The burning of fossil fuels has increased the carbon dioxide content of the atmosphere. What is a possible effect that the increased amount of carbon dioxide is likely to have on our planet?  
 (A) A warmer climate (B) A cooler climate (C) Lower relative humidity (D) More ozone in the atmosphere

Ex Output:

A