In the Revit.ini file, settings in the [ViewOptions] section correspond to settings on the General tab of the Options dialog.
DefaultViewDiscipline
Corresponds to the Default View Discipline setting on the General tab of the Options dialog.
Type = string
Valid values: Coordination, Architecture, Structural, Mechanical, Electrical, Plumbing
The default value varies, depending on which edition of Revit you are using.
Example
[ViewOptions] DefaultViewDiscipline=Architecture