John Has Been Hired by a Company to Conduct a Research

John has been hired by a company to conduct a research study on the factors that affect the attrition of employees in that company.John wants to prepare research objectives that would be able to represent and include in their scope the true feelings of the employees,for which he interacts with a few random employees.John recognizes the concept of:

A) quality.
B) attrition.
C) action standards.
D) frame of reference.
E) units of measurement.