SYMPTOM:
The Inherited Access option does not show up for projects in Strategy Developer 10.x as shown below:

CAUSE:
If the group to which the user belongs has no Security Role assigned, Inherited Access option will not be shown.
NOTE: all users objects belong to the Everyone group and in most cases the Everyone group does not have a security role assigned.
ACTION:
Assign a Security Role to the group, then the Inherited Access option will show up for the projects as shown below:

For more information on how to create/assign Security Role for a project, please check KB8051: How to create a security role for a specific project in MicroStrategy Developer 10.x .