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.
One example: Which event can cause a large rock to become soil over time?
(A) decaying (B) an earthquake (C) a landslide (D) weathering
Solution is here: D
Explanation: Under the action of heat, cold, rain, wind, and other atmospheric factors, the rock breaks down physically into small fragments that become the parent material of the soil. Also, atmospheric factors change according to weather.

Now, solve this: In 1879, Marie Cornu discovered that light from the Sun had a drop in ultraviolet (UV) light. Two years later, Walter Hartley found that ozone absorbs certain wavelengths of UV light. What motivated Charles Fabry and Henri Buisson to conduct research that led to the discovery of the ozone layer in the atmosphere of Earth?
(A) inquiring into the causes of observed phenomena (B) finding options for replacing missing wavelengths of light (C) health concerns about the effects of ultraviolet radiation (D) predicting future changes in ultraviolet light output
Solution:
A