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.

Ex Input:
In the late 1700s, Antoine Lavoisier performed a series of experiments to find out what happened when a substance burned. In each experiment, he observed that the weight of a container and its contents was the same at the end of the experiment as it had been in the beginning. These observations led him to propose the law of  
 (A) combustion. (B) fixed proportions. (C) conservation of mass. (D) conservation of energy.

Ex Output:
C


Ex Input:
A student notices a paw print while walking in a park. The paw print could be considered a fossil if the print was in ___.  
 (A) rock (B) topsoil (C) thick mud (D) loose sand

Ex Output:
A


Ex Input:
Scientists have shown that clearing the forest in the Amazon for farming is causing the extinction of native species. Which is the most direct cause of extinction from clear-cutting of land?  
 (A) pollution (B) habitat loss (C) climate change (D) use of fertilizers

Ex Output:

B