If you don't have the License Manager installed in the default location (C:\Program Files\ArcGIS\License), you need to figure out where it is installed.
Another possible location might be: C:\Program Files (x86)\ArcGIS\License
If it's not there and you're running the License Manager on Windows 7, just type License Server Administrator into the search box of the Start Menu. When the License Server Administrator pops up in the Startbar, right-click > Properties > Open File Location. This should take you to the installation directory of the License Manager.
If you're running the License Manager on Windows Server 2008 or 2012, you might try going to the control panel, hitting the View Menu and adding more columns. I believe there is an option in there to display the installation location.
In any case, once you've figured out the installation location of the License Manager, you want to ensure the options file is named 'ARCGIS.opt' and save it in the bin folder of the License Manager's install location. You'll then need to open the License Server Administrator and reread the licenses, which will pick up your options file. You can open the debug log after rereading your license file, scroll to the bottom and it there should be a line in there indicating that it is using the options file.