Final answer:
The incorrect statement about why Maria might be getting shocked is that there was a ground wire attached to the outlet, as a grounded outlet usually prevents shocks.
Step-by-step explanation:
The statement that is not a reasonable explanation for Maria getting shocked by her washing machine is: D. There was a ground wire attached to the outlet. The presence of a ground wire generally prevents electric shocks by providing a low-resistance path to the Earth, which should ensure that the case of an appliance is at zero volts. If Maria was getting shocked, it suggests a problem with the grounding system or with the washing machine's internal wiring. One possible explanation is worn insulation on the live/hot wire that comes into contact with the appliance's case.
Another reason could be the lack of a proper earth/ground connection, which can be particularly dangerous in areas with water that could provide a good path to the ground. Lastly, electricity flowing "downhill", points to the existence of a potential difference looking for the path of least resistance to the Earth, which can happen through a person if the appliance is not earthed properly.