Please answer the following question: Information:  - The Briar King is first novel of four in the series The Kingdoms of Thorn and Bone, by writer Greg Keyes.  - The Charnel Prince is a fantasy novel by Greg Keyes . It is a sequel to The Briar King and the second book of The Kingdoms of Thorn and Bone .  - Gregory Keyes is an American writer of science fiction and fantasy who has written both original and media-related novels under both the names J. Gregory Keyes and Greg Keyes.  - The Kingdoms of Thorn and Bone is the name of a fantasy novel series by Gregory Keyes, written between 2003 and 2008. They follow the story of Anne Dare, descendant of Virgenya Dare, a famed ruler who used her magic to aid the kingdom of Crotheny. Her descendants rule the kingdom until a traitorous plot to overthrow them leads to tragedy.    Given the information above, choose from the list below the object entity that exhibits the relation 'author' with the subject 'the charnel prince'.  Choices: - greg  - gregory keyes
Answer:
gregory keyes