There are 9 species in Spiral Horned Antelope.
7 are in East Africa
-Bushbuck
-Bongo
-Sitatunga
-Gedemsa
-Greater Kudu
-Lesser Kudu
-Nyala
In this genus only males have horns.
2 species of Eland farther north or west
In the 2 species both males and females have horns.
They are not as glamorous as the spiral horned specialties.
Spiral horned antelope.
Nyala, large spiral-horned African antelope
The Eland is a cowlike antelope. It is the world's largest antelope and is the animal most often illustrated in the early rock art of East Africa.
The antelope you are referring to is the "sitatunga." However, it does not end with a "d." If you meant to ask for an antelope with a name ending in "d," the "addax" fits the criteria but is not spiral-horned. Unfortunately, there isn’t a commonly known spiral-horned antelope that ends with the letter "d."
eland
Are you certain it begins with c? A kudu is a spiral-horned antelope.
eland
A nubuk is a misspelling of "nyala," which is a type of spiral-horned antelope found in southern Africa. They are known for their shaggy coat and long, twisted horns.
Addax
The scimitar oryx is a species of Oryx in Tunisia. It is a spiral-horned antelope.
NYALA
Several African antelope are ox like in appearance but the Greater and Lesser Eland are the most ox like in overall appearance. Wildebeest/Gnu has an ox like head as well.