Answer:
niche marketing
Explanation:
      College Prep Tutors uses a method of marketing technique known as niche marketing. Many advertising companies uses such marketing strategies.
      Niche marketing technique is a marketing technique which is used to target only a particular type of people. They remain focus to a particular kind and mainly focuses on particular age group of people, or a unique target market.
     In niche marketing, instead of offering the product to everyone, the product is focused on a specific group who would draw maximum benefits from the product.
Thus, College Prep Tutors uses "niche marketing" Â as a target marketing strategy.