Concept:A department store is a large retail unit that houses many different shops or departments together.
Explanation:The question describes “a number of shops under one roof.”
A department store fits this idea because it combines various sections, such as clothing, electronics, and food, all in a single building.
A chain store refers to multiple branches of the same shop in different locations.
A discount store sells goods at lower prices but is not defined by having many shops under one roof.
A unit store is a single, independent retail outlet, not a collection of shops.
Therefore, the correct option is the department store.
Answer:B. department store