Context: Read the text about capybaras.
What animal looks like a guinea pig and a hippopotamus? The world's largest rodent, the capybara! Also called capys, these animals enjoy being in wetlands and rain forest waters. They are strong swimmers that wade in mud to keep cool. Like guinea pigs, capys have short legs and chubby bodies with shaggy fur. Much like hippos, capys have their eyes, ears, and nostrils located high on their heads. This helps them check out their surroundings while staying mostly underwater. Staying out of sight is important when you're the favorite food of jaguars and snakes! Luckily, capybaras can hide underwater for five minutes at a time. Plus, their webbed toes help them paddle fast.
Capybaras live in Central and South America, usually in groups of between ten and forty. They eat plants like grass, reeds, grains, melons, and squash. They eat a lot of tough plants that are rich in fiber. To help break the plants down, capybaras have long teeth that chew side to side. They also have special bacteria in their guts that help break down fiber.
Though capybaras are happiest in the wild, they are easily trained. Zookeepers have taught these gentle rodents to walk onto scales to be weighed, go into crates, and sit still for physical exams. How do they do it? Food treats and belly rubs are fun rewards. Capybaras are so quick to learn that one was once used as a guide animal for a blind man in Suriname.
The capybara population is mostly stable, but capys are still threatened by deforestation. When large areas of trees are cleared, it reduces the capybaras' shelter. But now, people are starting to limit the number of trees people can cut in rain forests. This is good news for capybaras, as their home is being protected.
Which sentence correctly describes capybaras?
A. They are shy animals that usually hide in tall grass.
B. They are wild guinea pigs that live in mountain forests.
C. They are the closest relatives of the hippopotamus.
D. They are large rodents that are powerful swimmers.
Select the correct answer from the provided options and reply with the letter associated with it.

D