The correct answer is option 1: Cirrus. Cirrus clouds are the highest clouds in the atmosphere, located at altitudes of about 20,000 feet or higher. These clouds are thin, wispy, and white in appearance. They are composed mainly of ice crystals and are often found in the form of delicate, feathery strands or patches. Cirrus clouds are often an indication of fair weather or the presence of high-level jet streams.

Option 2, Stratocumulus, is a type of low-level cloud and is not the highest cloud. Stratocumulus clouds are lower in altitude and appear as large, puffy clouds with a flat base.

Option 3, Nimbostratus, is a thick, dark, and flat layer of cloud that stretches across the sky. It is associated with continuous precipitation, particularly light rain or snow. Nimbostratus clouds form at middle to low altitudes and are not the highest clouds.

Option 4, Cumulus clouds, are large, white, and fluffy clouds with a distinct flat base and rounded tops. They are usually found at low to middle altitudes and are not the highest clouds.

Therefore, the correct answer is option 1: Cirrus, as it is the