Multiple authors must be able to simultaneously make changes to a presentation.
Multiple reviewers have to be able to view one another’s changes after they are made.
One author and one reviewer work on a presentation at different times.
A i belive
B) Multiple authors must be able to simultaneously make changes to a presentation.
Co indicates being part of a whole. So this means that two or more authors are working on this project simultaneously. Such as co-management; two bosses working together in an equal position.