Barley is a cereal grain, and its scientific name is Hordeum vulgare. It is commonly grown for its edible seeds, which are used as food, animal feed, and in the production of beverages such as beer and whiskey.
- Triticum vulgare refers to wheat, another cereal grain, not barley.
- Vigna mungo is the scientific name for black gram (also known as urad dal), a legume, not barley.
- Oryza sativum is the scientific name for rice, a different cereal grain from barley.
Thus, the correct answer is option (2): Hordeum vulgare is the scientific name of barley.