Unit Testing Scenarios Question

[Yunying]

Hi~ In the rubric it says we should test four more scenarios for the Cashier. But I am still confused what counts as a complete scenario? Shall we just test the scenario like 1 waiter, 1 customer; 1 waiter, 2 customers; 2 waiters, 2 customers; 2 waiters, 2 customers with a market bill (which all look similar)?

Thank you!