-------Just for the context------- Imagine yourself sitting on a couch, with your friend in crime, in an empty motel room, talking with each other about this enormous diamond you stole 2 days ago from this super secret vault. You're stressing out over what's gonna happen next because the security always checks in on this diamond every 4 days, and, sooner or later, they're going to find out about what you both did. Your, not so bright, friend sees you, anxiously muttering something under your breath but decides to ignore it. After an hour, he/she comes back from the grocery store, yet you're still sitting on the couch, anxiously thinking about the next move. Finally, your, not so bright, friend comes up to you and in an attempt to calm you down, says this...
A) "No one is going to know if it happened!"
B) "No one is going to know it has happened"
What would be the correct option here? It's probably A); however, I don't really know why. So could anyone explain this to me in full depth?