The upper lip of bovine is short, thick and inflexible. The middle part of the upper lip and the region between nostrils are glabrous and moist, where is called ( ). A: Nasolabial gland B: Nasolabial speculum C: Rima oris D: Angulus oris

鼻被鼻中隔分为左右两个鼻腔，鼻腔经鼻孔开口于面部，经鼻后孔与咽部相通。 A: Nose is subdivided into a left and right canal by the nasal septum. Each canal opens to the face by a nostril and into the pharynx by the choana. B: The nasal septum divides the nose into the left and right nasal cavities, which open in the face through the nostrils and communicate with the pharynx through the posterior nasal foramen.