Which statement best compares the impact of population size in these two countries?

A. If China and Pakistan have the same population size, the population density of Pakistan would be higher.
B. If China and Pakistan have the same population size, the population density of Pakistan would be lower.
C. If China has a higher population size than Pakistan, the life expectancy there would be higher.
D. If China has a higher population size than Pakistan, the mortality rate would be lower.