Task: Question Answering
Input (English): 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. 
Question: Who is told to go train under Yoda?
Output (English): Luke.