Context: Read the passage. Then answer the question below.

In the Sandhills region of Nebraska, a grassy prairie grows on sand dunes. The roots of grasses, such as the prairie sandreed, help hold the sand in place.
Greater prairie chickens roam through the grasses eating seeds, leaves, and insects. Adult prairie chickens are prey for coyotes, great horned owls, and red-tailed hawks. Their eggs can be eaten by raccoons, skunks, and red foxes.
Figure: greater prairie chickens on a Nebraska prairie.
Which of the following best describes an ecosystem on a prairie in Nebraska?
A. the sand dunes, the prairie sandreed, and the greater prairie chickens
B. the red foxes
C. the seeds, the leaves, and the insects
Answer with the option's letter from the given choices directly.
Answer: A