Task: Question Answering
Input (English): Passage: In Billings, Montana, a police officer arrives and discovers Woody Grant walking on the shoulder of the roadway. Woody is picked up by his son David, who learns that Woody wants to go to Lincoln, Nebraska, to collect a million dollar sweepstakes prize he believes he has won. When David sees the sweepstakes letter, he knows immediately that it is a mail scam designed to get gullible people to purchase magazine subscriptions. David brings his father home, where his mother Kate becomes increasingly annoyed by Woody's insistence on collecting the money.
After Woody is picked up again trying to get to Nebraska, David and his brother Ross discuss putting Woody in a retirement home. David pays a visit with his ex-girlfriend, Noel, who returns his belongings and refuses to move back in with him. Their conversation is cut short by a call from Kate reporting that Woody has taken off once again. David retrieves Woody and decides to drive him all the way to Lincoln, much to Kate's dismay.
While in Rapid City, South Dakota, Woody goes on a bender and hits his head while stumbling back to their motel room. David takes him to the hospital to get his head stitched up. David learns that they will be passing through Woody's hometown of Hawthorne, Nebraska, and suggests they spend the night with Woody's family. Woody is against the idea, but they end up going anyway.
They stay with Woody's brother Ray, his wife, and their two sons, Cole and Bart. Woody and David visit a mechanic shop Woody once co-owned, followed by some beers at a bar. When David brings up Woody's alcoholism and problems within the family—with Woody implying that he did not love Kate nor really want children—they get into an argument. At another bar, they meet Ed Pegram, whom the family blames for stealing Woody's air compressor decades ago. Over David's objections, Woody mentions winning the money and the barflies toast his good fortune. The next day, they learn that the news has spread through the town like wildfire. 
Question: Who are Woody and Kate's children?
Output (English): David.