Given the task definition and input, reply with output. 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: Marijuana-smoking, Grand Rapids slacker pizza delivery driver Nick has trouble completing the "30 Minutes or Less" policy and is reprimanded by his boss Chris. Nick's school teacher friend Chet discovers that Nick slept with his twin sister, Kate, on the night of their high school graduation, causing Nick and Chet to end their friendship. Dwayne Mikowlski and Travis Cord, are miserable living under the shadow of Dwayne's domineering father, The Major, who about 10 years prior won over $50 million in the lottery. Dwayne confides in lap-dancer Juicy about his contempt for his father and Dwayne's presumed inheritance. At Travis's suggestion, he and Dwayne devise a plot to kidnap a complete stranger and strap a remote-controlled bomb to his chest. They order a pizza and wait for a driver to come to their hideout. When Nick arrives, Dwayne and Travis assault him and knock him unconscious.
Whose sister did Nick sleep with?