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]: Surface mining is a type of mining that is done at the surface of Earth. In addition to supplying valuable minerals to industry, surface mining might also  
 (A) discourage landfills. (B) increase Earth's surface area. (C) eliminate groundwater pollution. (D) create recreational ponds and lakes.
[A]: D


[Q]: A container is filled with a mixture of sand and an unknown substance. What should a student do to determine whether iron particles are in the mixture?  
 (A) heat the mixture (B) filter the mixture (C) pour water into the mixture (D) pull a magnet through the mixture
[A]: D


[Q]: Ptolemy was an ancient astronomer who thought Earth was the center of the universe. When he made observations that were inconsistent with this, he proposed a phenomenon called "epicycles" to explain the observations. How was Ptolemy's process similar to the modern scientific process?  
 (A) Ptolemy based his model partly on a belief system. (B) Observations inspired Ptolemy to modify his explanations. (C) Ptolemy tried to describe the universe instead of explaining it. (D) Experiments were the basis of Ptolemy's model of the universe.
[A]:
B