A: Two weeks. Three if you bought good steak.
That's how long we leave steak out in my family. My father ate pounds of what you call "rotten steak" every day of his life until he finally passed away at the ripe old age of 38.
I can't recall exactly what killed him. I was a mere boy when he passed. I remember him vomiting constantly, or sitting in his favorite chair, shivering, white as a ghost, as sweat rained down his face and he struggled to breathe. I think he had lupus. Or got hit by a truck. I'm sure it had nothing to do with his diet.
So, how do you want your steak cooked? I like my medium rare - that keeps the steak tender, but kills all the vermin.