How to enable: "Activate Plugin Per Site Basis"

How do I enable: "Activate Plugin Per Site Basis"

Cannot find the option?

I want to INSTALL a plugin on SELECT blogs (manually if I have to), because one of my plugins (WProbot) needs it done that way.

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Menu Settings

"Enable administration menus [X] Plugins"
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Enabling Plugins does NOT have the options to "Install" a plugin. :slight_frown:

Thanks!