The coldest temperatures in the atmosphere occur in the Mesosphere, which can reach as low as -90 degrees Celsius. This layer is found above the Stratosphere and below the Thermosphere. Therefore, the correct answer is B: Mesosphere. ;
The layer of the atmosphere with the coldest temperatures is the Mesosphere, where temperatures can drop to around -90 degrees Celsius. The correct answer to the question is B: Mesosphere.
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