Answer:
The used it as shop
Step-by-step explanation:
The ancient Romans were known to have a form of storey building structures known as Insulae. This storey building is usually divided into different apartments and floors. The ground floors of the buildings were most of the time inhabited or taken by traders and used as shops.
Hence, in this case, the correct answer is the Romans used the ground floor rooms of their homes that face the street as SHOPS.