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]: The fossils of dinosaurs that lived millions of years ago can be found in  
 (A) the water of oceans. (B) the ice on ponds. (C) the trunks of trees. (D) rocks in the ground.
[A]: D


[Q]: Which form of energy are x rays and ultraviolet light?  
 (A) nuclear (B) heat (C) electromagnetic (D) chemical
[A]: C


[Q]: Which statement best explains how periods on the periodic table are organized?  
 (A) increasing atomic number from left to right (B) increasing number of neutrons from left to right (C) decreasing number of electrons from left to right (D) decreasing atomic mass number from left to right
[A]:
A