Answer:
The correct answer is round character.
Step-by-step explanation:
The English novelist, short story writer, and essayist E. M. Forster described in his book, Aspects of the Novel, the two main types of characters in a work of literature; round characters and flat characters.
Flat characters are described by him as two-dimensional, relatively uncomplicated and with not changes characters. On the other hand, round characters are described by this same author as complex, undergo development, and able to even surprise the reader.
Bearing in mind the described above, it coul be said that A character in a fictional work that is very well developed is called a round character.