Is it possible to create an active full backup manually?
A. Yes, but only via PowerShell.
B. Yes, but only using the Active Full option from the shortcut menu of a corresponding job.
C. No, active full backups can be created only according to the schedule.
D. Yes, but only if the forward incremental backup mode is used.
E. Yes, using the Active Full option from the shortcut menu of a corresponding job or through PowerShell.
E is correct
Correct anwser is E
You can launch active backup with powershell
https://helpcenter.veeam.com/docs/backup/powershell/start-vbrjob.html?ver=95u4