Because this old woman selling vegetables can be called an old woman selling vegetables.

Selling vegetables refers to the behavior of vendors selling vegetables or farmers producing and selling vegetables themselves. Vendors often go to vegetable wholesale markets to buy back vegetables at wholesale prices and then sell them to earn the difference. We call them vegetable sellers or vegetable sellers. Some farmers pull their vegetables to the streets, markets or vegetable fields, roadsides and other places for sale. People used to call them vegetable sellers.