What type of air is characterized as calm with stratiform clouds and continuous precipitation?

Stable air is characterized by a calm atmosphere, where the layers of air exhibit a tendency to resist vertical movement. This condition often leads to the formation of stratiform clouds—layered clouds that typically cover the sky uniformly and are associated with steady, continuous precipitation. In stable conditions, there is not much turbulence, allowing for the development of these smooth, broad cloud formations rather than the towering cumulus clouds associated with unstable air.

When stable air is present, the vertical temperature gradient is such that it inhibits rising motions, leading to a more uniform and steady weather pattern. This continuous precipitation is usually light to moderate and can last for extended periods, as opposed to the abrupt, intense rainfall more commonly seen with unstable atmospheres.

Overall, the characteristics of stable air align perfectly with the conditions described in the question, making it the correct answer.