The right option is; D. waterfall
Waterfall is the feature that the Nacunday National Park is known for. Ñacunday National Park is a national park that is situated in Paraguay. Inside the Ñacunday National Park is a large waterfall known as Salto Ñacunday Waterfall which gives the park its uniqueness. The waterfall is the most important waterfall in the country and it is about 40 – 35 meters in height and 110 meters wide.