I chose c. I called 911. I was freaked out. I couldn't hear if there was someone walking upstairs because the furnace was blaring at the end of the hall downstairs.
They came, told me better safe than sorry, said they were happy I had a big, scary sounding dog- she barked crazy style when she saw them flashing their lights into the house and when she saw them standing on the porch, and then offered to come in and make sure the house was secure. I told them there was no need that if someone had been here they would have been flushed out once Josie came upstairs to bark at them. They agreed, but asked a few more times.
The reason I did not just come up with her was she's still dopey. She's on barbiturates. She's not herself yet (although each day we see her returning to her normal self more and more). So I didn't want to put her in that position.
I felt stupid, but at the same time justified. It seriously sounded like someone had dropped in through a window (although all our windows are locked) and I swear (before the furnace kicked on) it sounded like a footstep or two happened right after.
I am amazed that the answer was unanimous and everyone said they'd go up with the dog. Then again, I would have said that too, had it not been me. I'm normally an investigate kind of person. But the adrenaline was kicking, I was shaking and really scared (which I don't ever remember being that scared before). So there we have it. I chose c. call 911.