In an area populated by following species would have largest population a foxes b rabbits c grasshoppers field mice?

The species with the largest population in this area would likely be grasshoppers. Here's why:

* Food Chain: Grasshoppers are primary consumers, feeding directly on plants (grass, etc.). This means their food source is abundant and readily available.

* Reproductive Rate: Insects like grasshoppers have a very high reproductive rate. They can lay hundreds of eggs at a time, and multiple generations can occur in a single year.

* Habitat Suitability: Grasshoppers are adapted to a wide range of habitats, including grasslands, which is likely the environment described.

While the other species mentioned are also important parts of the ecosystem, their populations will be limited by:

* Rabbits: They are herbivores, but they face predation from foxes and field mice.

* Foxes: They are predators, and their population size will be dependent on the availability of prey, like rabbits and mice.

* Field Mice: They are small mammals, and their populations can fluctuate due to predation, food availability, and disease.

In general, the lower on the food chain a species is, the larger its population can be. Grasshoppers, as primary consumers, have the advantage in this scenario.