In an Observational Study of Manifestations of Various Categories of Sundowning

In an observational study of manifestations of various categories of sundowning behavior in hospitalized super-elders, which of the following are true?

A) Checklists based on a rating scale would be helpful ways to records behaviors.
B) Rating scales of 1-absent, 2-slight, 3-moderate, and 4-severe could be used.
C) A category system should be developed before the study begins.
D) The patient's assessment of whether or not he or she is sundowning is valuable.
E) There should be no overlap of the categories "confused, placid" and "confused, agitated."
F) Research assistants observing the patients should be given similar training.
G) Observations should be made under similar circumstances.