Answer:
The correct answer is option D. made up.
Explanation:
The definition of the fictitious word is something that is not real, but made up.
In this case the definition is clear, but there are times that you can find words that can have more than one meaning, so you should pay attention to their context.
Context are all those words that are "around" the word you want to define. If you did not know the meaning of a certain word, it would be enough to understand its context to realize what it means.
In this case we have the phrase "but they felt real to him", that "but" indicates that the fictitious word is something contrary to the real thing, that is, that the characters are made up.
