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
The first to appear in a cause of acute intestinal obstruction is - 
Select and explain. 
A. Constipation, B. Colicky pain, C. Vomiting, D. Distension
B: Colicky pain
Answer: B: Colicky pain 
Explanation: • Symptoms of intestinal obstruction: Pain, vomiting, distention and constipation
• Pain is the first symptom encountered; it occurs suddenly and is usually severe.
Pain in Intestinal Obstruction
• It is colicky in nature and is usually centred on the umbilicus (small bowel) or lower abdomen (large bowel)
• The pain coincides with increased peristaltic activity
• With increasing distension, the colicky pain is replaced by a mild constant diffuse pain
• The development of severe pain is indicative of the presence of strangulation
• Pain may not be a significant feature in postoperative simple mechanical obstruction and does not usually occur in paralytic ileus