A 45-year-old woman, with aa history of gallstones for the past 2 years, has recurrent episodes of biliary colic that require short ER treatment with analgesics and antispasmoic. This time she develops a similar type pain but of a much severe intensity associated with fever and nausea. She appears exhausted and tired, temp 36.6 C, right hypochondrial tenderness with a positive murphy’s sign. Lab work shows a WBC 20, Neu 88%, AST and ALT are normal, total bilirubin is normal. Which of the following is the most likely diagnosis?