Final answer:
The correct answer is that a disgruntled customer will tell between 5-10 people about their experience. This fact is crucial for businesses since customer service can strongly influence reputation through word-of-mouth.
Step-by-step explanation:
The sentence 'Most experts estimate that a disgruntled customer will tell between 5-10 people how they were treated' is the one that most accurately fills in the blank with the estimated number of people a dissatisfied customer will likely inform about their poor treatment or experience. This phenomenon is essential for businesses to consider, as word-of-mouth can significantly impact a company's reputation and customer base. Understanding customer behavior patterns, such as the rate at which customers arrive at a store or the expected number of long-distance calls during peak times, is pivotal for business operations and customer service strategies. For example, if a store expects one customer every two minutes on average, then it would take approximately six minutes for three customers to arrive.