Concept:
The atmosphere is divided into layers by height: troposphere, stratosphere, mesosphere and thermosphere, from lowest to highest. Each has distinct properties.
Step 1:
The lowest layer, touching the Earth's surface, is the troposphere. It contains most of the atmosphere's water vapour and air mass.
Step 2:
Because almost all the moisture and vertical air movement is here, clouds, rain, storms and essentially all weather take place in the troposphere. The higher layers are calm and dry by comparison.
Answer: Option (4) — Troposphere.