Which of the following statements regarding the acute abdomen is correct?
A. The parietal peritoneum is typically the first abdominal layer that becomes inflamed or irritated.
B. An acute abdomen almost always occurs as the result of blunt trauma to solid abdominal organs.
C. The initial pain associated with an acute abdomen tends to be vague and poorly localized.
D. The most common cause of an acute abdomen is inflammation of the gallbladder and liver.