Teacher: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.
Teacher: Now, understand the problem? Solve this instance: In an investigation, a student wants to see how a ball is affected by rolling it over a surface covered with sandpaper. In preparation for the trial, the student makes a list of the possible conditions that could affect the investigation. The student is most likely listing the
(A) constants. (B) variables. (C) controls. (D) trials.
Student:
B