The image provided is a photomicrograph of a transverse section through part of the gas exchange system. Which statement best describes the image?
- Aa thin inner layer of ciliated epithelial cells on top of a layer containing cartilage, supported by elastic fibres
- Ba very thin epithelial lining with walls containing elastic fibres, surrounded by many blood vessels
- Can inner layer of ciliated epithelial and goblet cells on top of elastic fibres, supported by an outer layer consisting of cartilage
- Dan inner layer of ciliated epithelial and goblet cells on top of loose tissue with mucous glands, supported by a continuous ring of cartilage