Answer:
Word of mouth.
Explanation:
Word of mouth publicity or marketing strategy is very reliable and essential to grow. It is free of cost publicity where consumer spread company´s brand name with the experience they had. Here, each customer could bring hundred of customers if had positive experience with the goods and services of the company. This publicity have a power of getting many loyal customers as experienced customer put their credibility on line. It also help the company to penetrate in the market and grow their market share. To encourage customer, companies also come up with different campaign or promotion plan for loyal customers.