Which of the Following Is an Example of Internal Marketing

Which of the following is an example of internal marketing conducted by a chain of dog kennels that boards and grooms pets? 

A)  A public relations article in a local paper describing the training received by the kennel's employees.
B)  An e-mail to one of the employees praising him for finding and returning a customer's dog collar.
C)  A newspaper ad showing a picture of happy dogs staying at the kennel.
D)  A tour of the facilities available at the kennel for elementary school children.