>>719139121
It's pick your poison really.

>Destroy
removes every artificial intelligence and the mass relays from the galaxy, effectively leaving most systems permanently isolated from one another. not only would the cool geths and EDI be destroyed, a bunch of ships and services that relied on artificial intelligence would also be fucked.
>Control
unstable, and it probably only delays another conflict with the reapers later on. It'll perhaps be even worse when the time comes, considering they got Shepard.
>Synthesis
very suspicious amalgamation of biological and machine intelligence (how the fuck would that even work? It makes no sense). Who knows what the consequences of fusing with the reapers would be.

All in all, unfortunately I guess I'd pick destroy. It's the 'safer' option.
Though in retrospect, doesn't the explosion of the mass relays destroy practically the entire system where it was present?