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.

[EX Q]: Some plant species are more tolerant of acidic soil than others. The tolerant species are favored in areas affected by which consequence of human activity?  
 (A) mixing of pollutants with rain (B) erosion of topsoil by clearcutting (C) runoff of fertilizer used in farming (D) thinning of the atmospheric ozone layer
[EX A]: A

[EX Q]: What season is the Northern Hemisphere experiencing when it is tilted away from the Sun?  
 (A) spring (B) summer (C) autumn (D) winter
[EX A]: D

[EX Q]: Overuse of soil for farming causes local disruptions of several Earth subsystems. Which of these is a part of the biogeochemical cycle that experiences the most severe local disruption?  
 (A) release of carbon into the atmosphere (B) release of oxygen into the atmosphere (C) cycling phosphorus into the soil (D) cycling hydrogen into the soil
[EX A]:
C