Final answer:
The restaurant manager or FOH manager is responsible for handling guest complaints, training staff, and opening the restaurant on time. The lunch-hour manager addressed a line-up issue by introducing floor markings, resulting in an efficient service and reduced staff stress.
Step-by-step explanation:
The individual responsible for solving all guest complaints, training the FOH (Front Of House) staff, and ensuring the restaurant opens on time is typically the restaurant manager or a specific management role designated for the front of house operations, such as a FOH manager. In the context provided, a lunch-hour manager was tasked with these responsibilities.
When faced with guest complaints about a confusing line-up system, the lunch-hour manager took action by implementing a new system with clear floor markings to indicate where customers should line up for each cashier. As a result of this initiative, the customer service clerks experienced less stress and the restaurant was able to serve a higher number of customers more efficiently.