Duct leading from parotid gland and opening into vestibule is
(a) Haversian duct
(b) Stenson's duct
(c) Wolffian duct
(d) Infra-orbital duct
(b) Parotid glands are largest salivary glands. Saliva is secreted by Stenson's duct which open opposite to the second upper molar tooth.