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.

Passage: Mickey Mouse, Donald Duck and Goofy are on a whaling boat in search of whales. Donald tries to eat a sandwich for lunch, but seagulls bother and harass him to get the sandwich and end up eating most of it. While Donald is preoccupied with fighting off the gulls, a pelican eats the remainder of the sandwich. Meanwhile, Mickey tries to pitch a bucket of water off the ship, but it keeps coming back to him, to his annoyance. Donald and Goofy spot a sleeping whale, but Goofy's efforts to shoot a harpoon keep failing because he doesn't have all the tools needed (at one point, he sets his own bottom on fire). He eventually succeeds in launching the anchor in plaace of the harpoon, but his foot gets caught in the attached line and when the anchor hits an iceberg he ends up hanging from the line above the whale's head.
Donald rushes to Goofy's rescue, but isn't fast enough and Goofy falls off the line, through the whale's blowhole, and ends up in the whale's mouth. Lighting a match so he can see better, Goofy inadvertently wakes the whale up and it starts coughing. A wave comes in through the whale's open mouth and washes Goofy around. He gets blown out of the whale's blowhole and falls back down, his head getting stuck in the blowhole. Meanwhile, Donald falls into the water and is chased by the angry whale back to the ship, where, after Donald is nearly eaten, the whale rams and destroys the ship. Mickey, Donald and Goofy fly through the air and land on a small raft made of the ship's debris. Goofy ends up with a fish in his hands, and, believing it is the whale, says, "Gosh, must have shrunk!".
What kinds of birds eat the duck's sandwich?