Assuming influencing factors are reasonably stable, which of the following forecasting techniques would be the most accurate for estimating the number of replacement invertor batteries that will be purchased by Indian consumers next year?

1. Trend projection Here data of past sales is used to project future sales. This is the simplest and most straightforward method of demand forecasting. 2. Market research This is based on data from customer surveys. Time and effort is required to prepare and send out surveys and tabulate data. 3. Sales force composite This method uses the experience of the sales team in a company. Feedback from the sales group is used to forecast customer demand. 4. Delphi method Demand forecasting experts from outside the firm are involved in this method. Several rounds of questionnaires are held which are to be responded anonymously until the group of forecasting experts comes to a consensus. 5. Econometric A mathematical formula is created to predict future customer demand. Here, statistical tools and economic theories are combined to estimate the economic variables and to forecast the intended variables.