When you create a system to manage all of your observational data, you must ensure that

a. files are organized chronologically so you can see what a child did on a given day.
b. children's records are kept confidential according to the family educational rights and privacy act (ferpa).
c. files include data on all domains.
d. data is accessible so that people can find the information they're looking for.

The correction option is A.
When you create a system to manage your observational data, it is important that the files should be well arranged in order to make it easier for you to retrieve any file you need in the smallest amount of time. To make this possible, the file could be arranged in a chronological order, that is, in the order in which they happen, so that it will be easier for you to see what happens on a daily basis.