Answer: The difference between the two economist are "differences in perception versus reality". That means option B is most correct.
Explanation: The difference in their perception versus reality, means how their want to interpret things against how things really are.
Harry interpret his understanding, that the way people save their house hold is becoming lower than what it use to be, to improve the standard of living. Though he doesn't believe consumption of household product is the factor to be controlled to achieve an improvement in the standard of living. While Edison interprets his that, if tax is applied more in consumption, it will help reduce the rate of consumption of households products, which will help them to save more, thereby increasing their standard of living.
Harry views household consumption as a real factor of standard of living that has been affected due to a cause. While Edison views household consumption as the real cause, which has to be worked on, to achieve a growth in standard of living.