Why be good?

[Iroscato]

...So as suspected, the only thing stopping you from becoming an axe murderer is because you think Sky Daddy is watching you.
You might think you're some maestro in the art of bullshit, but I'm afraid it's remarkably easy to cut through.

It's not just that I think He's watching...though that is true of all of us, you included. 

It is that He helps us avoid things which are not good - if we ask for help.

A man goes on a business trip to Las Vegas. He's alone and decides to have dinner in the hotel restaurant/casino. He's eating at the bar, when an attractive woman sits down next to him. She's a hooker, and he knows it. 

Does he say, "No thanks" because God is watching? Or because he loves God and wants to avoid sins which separate him from God?

That's the exact same fucking thing, moron - your attempts to garnish option A with word salad aside.
Option C - he decides the benefits of intercourse with the extremely attractive woman will outweigh the negatives, takes her back to his room and bangs the Holy Ghost outta her.