Answer: Option (A) is the correct answer.
Explanation:
Usually, density is defined as mass present in per unit volume.
Mathematically, Density =
Since density is directly proportional to mass so, more is the mass of an object more will be its density.
Similarly, population in terms of density is the number of organisms of a species per unit area.
Thus, we can conclude that out of the given options the number of organisms of a species per unit area MOST closely defines population density.