what does it mean to say that a country's land area is positively correlated with its population?

a The larger land area of a country, the higher its population tends to be
b The smaller the land area of a country, the higher its population tends to be
c There is no relationship between a country's land area and its population
d a larger land area automatically means a higher population

a The larger land area of a country, the higher its population tends to be