The correct answer is - b. number of populations land area.
The density of the population is very simple to be calculated. We only need two information's, the number of the population, and the land area where that population lives. Than we divide the number of the population with the land area and we get the result of the density of the population.
Number of population / land area = population density.
For example:
652,008 / 13,404 km² = 48,64/km²
