What best describes customer service?

A$.$ The customer is always right

B$.$ Customer service is the provision of service to customers before, during and atter a purchase

C$.$ Customer service is the process by which an organization delivers its services or products in a way that allows the customer to access them in the most efficient, fair, cost effective, and humanly satisfying and pleasurable manner possible

D$.$ Serving the customer as they would prefer to be served. As a transit organization, being on time with warm$/$cool $($depending on the season$)$ trains is of utmost importance.