Detailed Instructions: 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.
Q: Students from two classes conducted the same investigation. Each class got different results. Which is the best way for the students to determine why the results were different?  
 (A) Review the steps taken during the investigations. (B) Change the hypothesis of the investigation. (C) Research data on similar investigations. (D) Conduct a different investigation.
A:
A