Final answer:
A hospital emergency room does not follow the FCFS discipline, as patients are served based on the urgency of their conditions rather than arrival order.
Step-by-step explanation:
The waiting line system that does not use the First-Come, First-Served (FCFS) service discipline to serve people is c) A hospital emergency room. In hospitals, especially in emergency rooms, patients are typically triaged based on the severity of their conditions, rather than being served strictly in the order they arrive. This is essential to ensure that those with life-threatening issues receive immediate care.
In contrast, settings such as fashion retailers, gas stations, and fast food restaurants usually follow a more straightforward FCFS approach, where customers are served in the order they arrive or queue.