Please answer the following question: Who is the sister of the twins' mother?  Answer the above question based on the context below:  Chicagoan Chester "Chet" Ripley, his wife, Connie, and their two sons, Buckley "Buck" and Ben, are on vacation at a lake resort in Pechoggin, Wisconsin during the summer. All is going as planned until Connie's sister, Kate, her investment broker husband, Roman Craig, and their twin daughters, Mara and Cara, crash the vacation. Ghost stories at the family BBQ include one of a man-eating grizzly bear that Chet met face-to-face when he was younger. Chet says that while he and Connie were honeymooning at the same lake, he was attacked by a giant grizzly bear. When he fired at it with a shotgun, the buckshot shaved the hair off the top of the bear's head and from that day on, it was known as the "Bald-Headed Bear" of Claire County. After Roman pulls Chet around the lake on an impromptu water ski ride with his rented speedboat, tensions between the families erupt. Chet is ready to pack up and go home, even as his teenage son Buck tries to romance a local girl, Cammie. The budding romance goes well until Chet is challenged to eat the Old 96'er (a 96-ounce steak) at a family dinner which causes Buck to break their date. Buck tries to apologize to Cammie for being late, but Cammie refuses to speak to him. Connie and Kate bond at a local bar when the conversation drifts to Kate's challenges of being wealthy. Later, just at the peak of tension between families, it emerges that Roman has made a bad investment and is broke. He has not told Kate and was planning to hit up Chet for the cash. Later, during a thunderstorm, the twins wander off and fall into a mine shaft. Chet and Roman find them, but the claustrophobic Roman is reluctant to descend into the tiny mine shaft. After some encouragement from Chet, Roman summons up all his courage, while Chet goes in search of a rope to pull them out. Upon realizing that the mine is stocked with old dynamite, Roman takes his daughters and climbs out of the shaft on his own.
A:
Connie