Problem: What type of thing is the question "What J.R.R. Tolkien book features Bilbo Baggins as the central character ?" asking about?
Answer: entity

Problem: What type of thing is the question "Who was the Democratic nominee in the American presidential election ?" asking about?
Answer: human

Problem: What type of thing is the question "What is IOC an abbreviation of ?" asking about?
Answer:
abbreviation