Verified Answer :

I think the answer is Cirrus. They are flat feathery clouds that usually stretch long distances over the sky.

Stratus –layered or sheet like, low (50 - 6500 feet)

Cumulus – puffy cotton balls, vertical development

Nimbus – dark and rainy

Cirrus – feather-like, high (20 000 feet)

Alto – medium altitude (6500 - 20 000 feet)