In this task, you will be shown an extract from a movie plot. You need to read the extract and create questions that can be answered from the extract. The questions should be well-formed and grammatically correct. The questions should be completely answerable from the given passage and should not require any external knowledge. Subjective questions are not allowed. Create questions that result in factoid answers. A simple rule of thumb to decide whether a question is factoid or not is to see if two different people with average reading/comprehension skills would come up with the same answer after reading the passage.
Q: The movie starts out with a meeting between the rulers of Baekje, Silla, Tang China, and Goguryeo. They are arguing why the Korean southern kingdoms have to pay tribute to China, even though Tang is only 50 years old. The king of Silla sides with the Emperor of Tang. The movie flashes forward to the scene in which Baekje soldiers rush to the king with ill news of Silla and Tang allying together, bringing an army of 50,000 soldiers. The Baekje council discusses battle plans. But in the end, all of the officials run away out of cowardice. The king of Baekje calls for the great warrior, Kyebaek. He accepts the offer to protect his country after three glasses of wine. Kaebaek is forced to kill his family in fear of something worse happening to them. Soon, Gyebaek engages the Silla forces in so called "battles" where the opponents insult the others with Gyebaek winning in the beginning of these battles.
A:
To whom do the Korean southern kingdoms have to pay tribute?