Which of the Following Is TRUE Concerning the Collection of Data

Which of the following is TRUE concerning the collection of data to be used in estimating a cost function?

A) Data should contain observations for periods both before and after a major economic or technological change.
B) The time periods used to measure the outcome variable and the cost driver(s) should not be concurrent.
C) Both time series data and cross-sectional data are relevant, although both are not required.
D) All data should be viewed as being representative of the normal relationship between the outcome variable and the cost driver.
E) Data should contain observations for periods both before and after a major economic or technological change, and, both time series data and cross-sectional data are required.