Answer:
The answer is "Option a"
Step-by-step explanation:
The word "customer service" encompasses a broad variety of choices for help, which can be described as follows: 
- It helps in the interaction with service and quality, that depends on particular area service. 
 - It is about a client's view of a firm, that helps they got. It is an essential part of the ongoing development of business. 
 - In this service, its percentage rate is 70, that's why other choices were wrong.