Context: Caesars Entertainment executives have been reconsidering the future of their three remaining Atlantic City properties (Bally's, Caesars and Harrah's), in the wake of a Chapter 11 bankruptcy filing by the company's casino operating unit in January 2015.

Question: How many remaining properties belong to Caesars Entertainment?
Answer: three

Question: What are the names of the three remaining Caesars Entertainment properties?
Answer: Bally's, Caesars and Harrah's

Question: What type of bankruptcy did Caesars Entertainment file for?
Answer: Chapter 11

Question: What year did Caesars Entertainment file for bankruptcy?
Answer: 2015

Question: Which unit of Caesars Entertainment filed for bankruptcy in 2015?
Answer: casino operating unit