Teacher:Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
Teacher: Now, understand the problem? Solve this instance: King Bhumibol Adulyadej, the 9th king of the House of Chakri, became the longest reigning current monarch in the world during his reign of which country from 1946?
Student:
bhumibol adulyadej