Southwest Airlines hires people who are fun$-$loving and outgoing, who enjoy interacting with other people because putting fun into air travel is an essential ingredient of the company's culture. From a marketing perspective, this is an example of $\_\_\_\_\_\_\_\_\_\_.$

a$.$ The philosophy that the marketing orientation should permeate the organization, thereby making every employee responsible for customer satisfaction.

b$.$ The philosophy that employees will be willing to accept lower wages if they have fun at work.

c$.$ The philosophy that an organization's culture is the primary determinant of its marketing plan.

d$.$ The philosophy that when interpersonal relations at work are more amiable, everything will run more smoothly.