Answer: Unsought service
Explanation:
The unsought service is basically refers to the unsought goods where the goods are purchased due to the fear of the danger and the lack of the desire to buying the product or the services.
The reference books, encyclopedia and the fire extinguishers are some common examples of the unsought services.
According to the given question, the plumber service best illustrate the example of the unsought services.
Therefore, the unsought service is the correct answer.