This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Which of the following about acute pancreatitis is truea) Pain last for several hoursb) Serum amylase levels correlates with severity of attackc) Common in alcoholicsd) Low serum calcium levels indicate good prognosis 
Select and explain. 
A. a, B. bc, C. ac, D. b
C: ac
Answer: C: ac 
Explanation: None