Among the options given, the correct answer is d) flooding.
Density dependent factors are those that become more intense as the population density increases. This means that their effect on the population is related to the number of individuals in that population. Predation, parasitism, disease, and competition all fit this description because their impact grows as the population size increases. For example, in a crowded environment, there are more opportunities for predators to find prey, and diseases can spread more easily.
On the other hand, flooding is an abiotic factor that affects populations regardless of their density. Whether a population is large or small, a flood will have the same devastating effect on it. Therefore, flooding does not depend on the population density to exert its impact, making it the correct answer to the question.