Final answer:
An example of a density-dependent limiting factor among the choices is parasites, as their impact on a population grows with increasing population density.
Step-by-step explanation:
An example of a density-dependent limiting factor is c) Parasites. Density-dependent factors are environmental conditions that result in changes in population numbers and have different effects depending on the population density. Parasites are abiotic, or biological, factor and their effect on a population increases as the population density increases. This is because a denser population facilitates the spread of diseases caused by parasites, leading to higher mortality rates within that population. In contrast, density-independent factors, such as tornadoes or volcanic eruptions, affect populations regardless of their density.