You Have Responded to a Call of Patient at a Rural

You have responded to a call of patient at a rural location with difficulty breathing. As memory serves you, the farmhouse you are responding to has been abandoned for years. As you approach on the main road, you see several vehicles parked around the house, although it is apparent that the house is not in livable condition. For which of the following should you maintain a high index of suspicion?

A) The house may be structurally unsound.
B) The house is not the house you think it is, and is not abandoned.
C) The house may be serving as a clandestine drug lab.
D) The house has been occupied by a family who may be using a source of heat that releases carbon monoxide.