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Which best explains why there are gaps between the concrete sidewalks?
A When temperatures get cold, the gaps allow the concrete to expand without cracking.
B When temperatures get hot, the gaps allow the concrete to expand without cracking.
C When temperatures get cold, the gaps allow the concrete to contract without cracking.
D When temperatures get hot, the gaps allow the concrete to contract without cracking.
What is B? When temperatures get hot, the gaps allow the concrete to expand without cracking.