Question: What is the fourth novel in the cycle of books focused  on the adventures of a teenage boy named Eragon?
Sentence (from "Inheritance Cycle"): The series was originally intended to be a trilogy (named the "Inheritance Trilogy") until Paolini announced on October 30, 2007, while working on the third novel, that he believed the story was too complex to conclude in just three books.
Relevant evidence: No