In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Let me give you an example: Passage: Nearing London, Oliver encounters Jack Dawkins, a pickpocket more commonly known by the nickname the "Artful Dodger", and his sidekick, a boy of a humorous nature named Charley Bates, but Oliver's innocent and trusting nature fails to see any dishonesty in their actions. The Dodger provides Oliver with a free meal and tells him of a gentleman in London who will "give him lodgings for nothing, and never ask for change". Grateful for the unexpected assistance, Oliver follows the Dodger to the "old gentleman's" residence. In this way Oliver unwittingly falls in with an infamous Jewish criminal known as Fagin, the gentleman of whom the Artful Dodger spoke. Ensnared, Oliver lives with Fagin and his gang of juvenile pickpockets in their lair at Saffron Hill for some time, unaware of their criminal occupations. He believes they make wallets and handkerchiefs.
The answer to this example can be: Who believes Fagin's gang make wallets and handkerchiefs?.
Here is why: This question is based on the following sentence in the passage "He believes they make wallets and handkerchiefs". It evaluates the understanding that the pronoun "he" refers to name "Oliver". You can ask questions like this one about most pronouns in a paragraph.

OK. solve this:
Passage: Three years after the destruction of the Death Star, the Rebel Alliance, led by Princess Leia, has set up a new base on the ice planet of Hoth. The Imperial fleet, led by Darth Vader, continues to hunt for the new Rebel base by dispatching probe droids across the galaxy. Luke Skywalker is captured by a wampa while investigating one such probe, but manages to escape from the wampa's lair with his lightsaber. Before Luke succumbs to hypothermic sleep, the Force ghost of his late mentor, Obi-Wan Kenobi, instructs him to go to Dagobah to train under Jedi Master Yoda. Han Solo locates Luke and cuts open the tauntaun he rode there on to keep his friend warm; they wait there until being rescued by a search party the next morning.
Meanwhile, the probe alerts the Imperial fleet to the Rebels' location. The Empire launches a large-scale attack using AT-AT walkers to capture the base, which forces the Rebels to retreat. Han and Leia escape with C-3PO and Chewbacca on the Millennium Falcon, but the ship's hyperdrive malfunctions. They hide in an asteroid field, where Han and Leia grow closer amidst tension and briefly kiss. Vader summons bounty hunters to assist in finding the Falcon. Luke, meanwhile, escapes with R2-D2 in his X-wing fighter and crash-lands on the swamp planet of Dagobah. He meets a diminutive creature who reveals himself to be Yoda; after conferring with Obi-Wan's spirit, Yoda reluctantly accepts Luke as his student.
Answer:
Who is told to go train under Yoda?