Regarding Histamine, correct statement/s

i) It is a potent vasodilator

ii) It causes for nasal congestion

iii) It stimulates the secretion of pepsin in stomach

iv) It has one primary amine group

Histamine is a potent vasodilator. It has various functions. 

It contracts the smooth muscles in the bronchi and gut and relaxes other muscles, such as those in the walls of fine blood vessels. 

Histamine is also responsible for the nasal congestion associated with common cold and allergic response to pollen