The correct answer is option 3: Nimbus cloud. Nimbo or Nimbus clouds are rain-bearing clouds that are characterized by their dark and gray appearance. These clouds are typically associated with precipitation such as rain, snow, or sleet.

Let`s analyze the other options to understand why they are not rain-bearing clouds:

Option 1: Cumulus cloud. Cumulus clouds are puffy, white, and resemble cotton balls. While they can develop into rain-bearing clouds called cumulonimbus clouds, not all cumulus clouds produce rainfall.

Option 2: Stratus cloud. Stratus clouds are low-level clouds that are flat and featureless. They often cover the entire sky and may produce drizzle or light rain, but they are not typically associated with heavy rainfall.

Option 4: Cirrus cloud. Cirrus clouds are thin and wispy clouds that are high in the atmosphere. They are composed of ice crystals and are not rain-bearing clouds. Cirrus clouds often indicate fair weather.

In conclusion, the correct answer is option 3: Nimbus cloud, as it refers to rain-bearing clouds.