The complete oxidation of glycerol in prokaryotes provide how much ATP?

They give me this options 22ATP, 18 ATP, 21 ATP, 20ATP, 25ATP honesty if someone know the normal webside Quizlet does not have answer i will be so thanksfull and at the same time if you are a micro mayor can help for training this question are from Microbology class level 2010 is a pain class and medium hard will help a college student thanks you to anyone that can help again thanks.