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.

Example Input: Shale is a sedimentary rock that can be metamorphosed into slate by  
 (A) cementation. (B) chemical weathering. (C) sedimentation. (D) increased pressure.
Example Output: D

Example Input: Two workers are using a scaffold. One worker weighs 180 lbs. and the other weighs 200 lbs. Impact effects are assumed to increase the live load of the workers' weight by 25 percent. What is the resultant maximum live load, in pounds, that can be expected from the two workers supported by the scaffold?  
 (A) 380 lbs. (B) 475 lbs. (C) 625 lbs. (D) 950 lbs.
Example Output: B

Example Input: The human immunodeficiency virus (HIV) causes AIDS. The first known human cases AIDS were in Africa in the late 1950s. Since then, tens of millions of people have died from the disease, and tens of millions more people all over the world are infected. Which term best describes the disease AIDS?  
 (A) isolated cases (B) outbreak (C) epidemic (D) pandemic
Example Output:
D