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]: Which fact about water is an example of a chemical property?
(A) Water expands when it freezes. (B) The boiling point of water is 100C. (C) Water can separate into hydrogen and oxygen. (D) The density of water is greater than the density of ice.
[A]: C

[Q]: A school replaced all of their light bulbs with a new type of light bulb. The new light bulbs use less energy. How will the new light bulbs most likely help the environment?
(A) The amount of light pollution will decrease. (B) The air conditioner at the school will run less often. (C) Fewer natural resources will be used to make electricity. (D) Money will be saved on the electricity bill for the school.
[A]: C

[Q]: A "widow's peak" hairline in humans is coded by the dominant allele W. A straight hairline is coded by the recessive allele w. A man with a homozygous dominant WW produces a zygote with a woman with a heterozygous dominant Ww for the trait. Which allele combinations could occur in the zygote?
(A) WW or ww (B) WW or Ww (C) WW only (D) Ww only
[A]:
B