Which of the Following Is TRUE

Which of the following is TRUE?

A) A panel is a permanent or fixed sample of members from whom information is obtained continuously or at intervals over a period of time.
B) Nielsen's panels of households in which participants use a handheld scanner to record every UPC-coded item they purchase is an example of an omnibus panel in which the same variables are measured over time.
C) An omnibus panel is a fixed sample of individuals who are measured continuously (or periodically) with respect to the same information (e.g.,purchase diary) .
D) A true longitudinal analysis can be performed on data from an omnibus panel.
E) All of these statements are true.