Which list places the divisions of the geologic time scale in order, from longest to shortest? epoch, period, era period, era, epoch era, period, epoch era, epoch, period

The correct answer is - era, period, epoch.

The geological times scale is divided in general to eons, eras, periods, and epochs, and the reason for this is the better classification, studying, and division of the geological past.

The eras tend to be spanning for few hundred million years, the periods few tens of millions of years, while the epochs are spanning for few million years or few hundred thousand years.

The division is made, in general, when there's a drastic change in the climate patterns on a global scale, or an extinction event.