AppVolumes, UEM, vROps for Horizon - whichever versions were current when Horizon 7.7 was released.
App Volumes, UEM and vROps for Horizon versions are not mentioned in the Exam objectives
Ok, so using that idea Horizon 7.7 was released on 12/2018 and the next version(7.8) came out on 03/2019, here are the versions of products also released during that time.
UEM = 9.6
App Volumes = 2.15 (Hopefully only 2.x material is covered as the 3.x docs have been removed from the site)
vROps Horizon = 6.6 - 6.7
Hopefully this helps someone else.