Answer:
The correct answer is mesosphere.
Step-by-step explanation:
The atmosphere exhibits five distinct layers, which are determined by the modifications in temperature that take place with the upsurging altitude. These are troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Of the mentioned layers, the mesosphere, that is, the layer present above the stratosphere is considered as the coldest layer of the atmosphere. The coldest portions of the atmosphere are situated in this layer and can reach up to -90 degree Celsius.