Factors that limit population size are space, food, shelter, water, climate, competitive exclusion, and temperature. This means that the carrying capacity of an ecosystem, which is the total number of organisms it can support, will be limited. They can be abiotic or biotic. Abiotic factors that limit this capacity include sunlight, temperature, chemical environment... while biotic factors include food, predators, disease, competition for resources.
The abiotic limiting factor from the choices below is water. Correct answer: C