The correct answer is A. Trend analysis technique.
Trend analysis is a statistical method that uses historical data to predict future trends. It is a valuable tool for HR professionals who need to estimate future staffing needs. By examining past trends in employee turnover, hiring, and promotions, HR professionals can develop accurate forecasts of future staffing needs. This information can then be used to develop effective staffing plans and ensure that the organization has the right number of employees with the right skills at the right time.
Computer model technique and mathematical model technique are also useful tools for HR professionals, but they are not as accurate as trend analysis. Computer models are based on assumptions about future conditions, which may not be accurate. Mathematical models are based on complex equations that can be difficult to understand and use. Trend analysis is a simpler and more accurate method for estimating HR needs.
D is incorrect because trend analysis is a valuable tool for HR professionals.