Given the question: Question: What are the last names of the three Heathers? If there is no answer, please output "Insufficient information to provide an answer.". Movie title: Heathers Context: The most dominant clique at Westerburg High School in Sherwood, Ohio, consists of three wealthy and beautiful girls named Heather: the leader, Heather Chandler (Kim Walker), the quiet, bookish and bulimic Heather Duke (Shannen Doherty), and the weak-willed cheerleader Heather McNamara (Lisanne Falk). Though they are the most popular students, the Heathers are both feared and hated. They recently invited 17-year-old Veronica Sawyer (Winona Ryder) to join their group, by association making her a very popular girl as well. However, as the film begins, Veronica has had enough of their selfish behavior and longs to return to her old life and her nerdy friends. At school, a rebellious outsider named Jason "J.D." Dean (Christian Slater) pulls a gun on school bullies Kurt Kelly (Lance Fenton) and Ram Sweeney (Patrick Labyorteaux) and fires blanks at them. Veronica finds herself fascinated by this dark and quirky sociopath. When Veronica embarrasses Heather Chandler at a frat party by refusing sex and vomiting, Heather vows to destroy her reputation. Later, J.D. shows up at Veronica's house and they end up having sex after an impromptu game of strip croquet. Veronica tells J.D. she wants to make Heather puke her guts out. The next morning, Veronica and J.D. break into Heather's house. J.D. serves Heather a liquid he claims is a hangover cure but is actually drain cleaner, killing her. Although initially shaken by their act, J.D. regains his composure and urges Veronica to forge a dramatic suicide note in Heather's handwriting. The school and community look on Heather's apparent suicide as a tragic decision made by a popular but troubled teenager. Several days later, Kurt and Ram spread a rumor about Veronica giving them oral sex at the same time. To get even, J.D. proposes that Veronica lure them into the woods with the promise to "make the rumors true", then shoot them with what he promises are nonfatal "Ich luge" (which translates to "I'm lying" in German) German bullets that only break the skin but do no real...
The answer is:
Chandler, Duke and Mcnamara