Final answer:
A Cause and effect diagram, also known as a Fishbone diagram, is the graphic technique used to define the relationship between customer desires and a product or service.
Step-by-step explanation:
The graphic technique for defining the relationship between customer desires and product (or service) is called a Cause and effect diagram, also known as the Fishbone diagram. This tool is used to identify, explore, and display in a structured format, the possible causes of a problem, typically categorized to identify sources of variation. The Cause and effect diagram facilitates a team in categorizing the various potential causes of problems or issues in an orderly way and in identifying root causes.
Other graphical techniques mentioned, such as the scatter plot, is used for representing the relationship between two continuous variables and identifying patterns between them. The Pareto chart is a bar graph where the bars are displayed in descending order of frequency or size along with a line graph which shows the cumulative totals. However, these are not specifically used for defining the relationship between customer desires and products or services.