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.

[Q]: Typically, sedimentary rocks are formed  
 (A) only in erupting volcanoes. (B) only under great pressure and high temperatures. (C) below Earth's surface as magma cools and crystallizes. (D) from materials that settle.
[A]: D


[Q]: The Grand Canyon is an example of  
 (A) erosion. (B) deposition. (C) an earthquake. (D) volcanic activity.
[A]: A


[Q]: A student has decided to investigate whether the number of flowers on a plant will increase if the water supply to the plant is increased. She has five pots of geranium plants to use in her experiment. What factor in the experiment should be varied for the five plants in order to answer the student's question?  
 (A) age of seedlings (B) temperature of water (C) volume of water (D) number of hours in sunlight
[A]:
C