Answer:
c. make an accurate diagnosis of what is causing the problem
Explanation:
The manager of the fast-food restaurant should understand the underlying problem first. Working on the assumption that it's because of a competitor marketing campaign may not give the desired results. A customer's preference may change due to many reasons.
The manager should make an accurate diagnosis of the problem first. With a precise reason as to why customers as fleeing, then he can develop a counter-strategy. Retaining the current member of the crew will not reverse the situation. Reducing prices may affect profitability, which is not the desired result. With low prices, some customers may question the quality of the breakfast.