The ciliated columnar epithelial cells in humans are known to occur in
a)	Bronchioles and fallopian tubes	b)	Bile duct and oesophagus
c)	Fallopian tubes and urethra	d)	Eustachian tube and stomach lining

(a)

The columnar epithelium is composed of a single layer of tall and slender cells. If the columnar cells bear cilia on their free surface they are called ciliated columnar epithelium. They are mainly present in the inner surface of hollow organs like bronchioles, oviduct and fallopian tubes. Their function is to move particles or mucus in a specific direction over the epithelium.