Which of the following is referred to as the 'fifth P' of marketing?

A) Perception.
B) Psychology.
C) Person.
D) Participation.
E) Posting.

Participation is known as the fifth P of marketing, which refers to the role of engaging customers and encouraging them to participate in the marketing process through various means such as contests, social media campaigns, events, and loyalty programs. This tactic can help create brand loyalty, increase customer engagement, and generate positive word-of-mouth marketing.