Which Statement Expresses the American Marketing Association (AMA)'s Core Definition

Which statement expresses the American Marketing Association (AMA) 's core definition of marketing?

A) Marketing is a philosophy,an attitude,a perspective,or a management orientation that stresses customer satisfaction.
B) Marketing is an organization function and a set of processes implemented in order to ensure customer satisfaction.
C) Marketing refers to personal selling that focuses solely on selling goods,services,and/or ideas to customers.
D) Marketing involves building long-term,mutually rewarding relationships that are beneficial exclusively to the sellers.