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.

The best example of balanced forces is a  
 (A) car increasing speed. (B) bus parked in a garage. (C) ball kicked along a flat surface. (D) roller coaster slowing down on an incline.
B

In a lab investigation, students use Brand X batteries in a flashlight and Brand Y batteries in a radio. After two hours, the flashlight stops working, but the radio continues to work. As a result, the students conclude that Brand Y batteries last longer. Which statement about the conclusion of the investigation is most accurate?  
 (A) The conclusion is valid because they tested two different brands. (B) The conclusion is invalid because the test had multiple variables. (C) The conclusion is valid because they conducted the investigation in a lab. (D) The conclusion is invalid because the real names of the batteries were hidden.
B

Which process is most directly related to constructing new land?  
 (A) erosion (B) polluting (C) deposition (D) weathering

C