How can you hide Q&A plugin from subsites?

I have installed Q&A and would like to activate it on one subsite. the problem is that it appears on all subsites when network activated.
if it is network deactivated then it will not display in the subsite.

i tried to go to site setting and assign it to one specific site when network deactivated but this still didn't work and the plugin was not available to the subsite.

does anyone have a solution, or achieved running Q&A on one subsite without it being visible to other sites on the network?