Restrict access
From MoodleDocs
The restrict access feature enables teachers to restrict the availability of any activity or even a course section according to certain conditions such as dates, grade obtained, group or activity completion.
New in 31: Restrict access is enabled by default in new installations.
Note: If you don't see a 'Restrict access' option when setting up course activities and sections, check with the administrator that it is enabled in Site administration >Advanced features.