c) It's Elon.

Elon lies. If not all, his "announcements" have no source of truth. From SpaceX to Telsa, they are always exaggerated.

I don't dismiss that they've may of operated on someone implementing the chip but the realistic aspect of the chip not being rejected nor causing scar tissue would be the real news. In fact I doubt they've implanted it at all; this is just hyperbole to keep the hype going.

Maybe the future of the chip will enable you to move a mouse but in this instance I really doubt it.