Crowded living conditions lead to a significant decline in the health of citizens, which is a major problem facing City A. Because the areas and populations of City A and City B are the same, the above-mentioned problems that City A will face must occur in City B. Which of the following best refutes the above conclusions? ['Failure to accurately distinguish between the two concepts of population size and population density.', 'Failure to accurately distinguish between the concepts of area and population of a city.', "Crowded living conditions are the only cause of the decline in citizens' health.", 'Ignoring that the same population density can have different living conditions.']