Answer:
Product differentiation refers to "belief by customers that a product is unique".
Explanation:
Product Differentiation:
It is such a marketing strategy in which a business presents its products or services as "unique" by making it different from all of its products or services and from the products or services of its competitors.
For example:
If a company X offers some kind of special shoes that no other company is offering so that product is unique and it makes their customer feel special.