Teacher: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.
Teacher: Now, understand the problem? Solve this instance: Which action has most helped scientists find cures to some diseases?  
 (A) buying new equipment (B) learning about bacteria (C) finding chemicals in plants (D) avoiding poisonous animals
Student:
B