Task: Question Answering
Input (English): Question: One of the signs that can appear in the postoperative period is tympanism, which means: 
 Options:  <1> Paralysis of intestinal peristalsis. <2> Tympanic perforation due to increased pressure. <3> Evisceration <4> Retention of gases in the intestine. <5> Severe abdominal pain.
Output (English): 4