What terms apply to a well described character that is the protagonist's challenger?

1.a dynamic foil

2.a round antagonist

3.a static but major character

4.a round foil

The best answer to this would be option 4: A round foil. By description, when we say round character, this is the character that typically possesses a complex personality. This kind of character is usually the one that is conflicted in the story. In addition, when we say foil, this is the character that possesses qualities or beliefs that contradicts to that of the protagonist. Hope this helps.