Answer:
The correct answer is letter "C": 15-20.
Explanation:
Different researches have helped businesses concluded that around 15% to 20% of them lose their customers year after year. From them, almost 60% goes to the business's competitor and the other 40% substitute the good or service in reference. The main reason why individuals break up their relationship with companies is because of the treatment they received while others are dissatisfied with the good or service.
So, customer service is a key feature at the moment of determining clients' loyalty to the firm.