||While riding his bicycle, a 9-year-old boy loses control and falls. During the process, his abdomen strikes the handlebar. His parents bring him to the emergency department because he has vague midabdominal pain and some bruising of the anterior abdominal wall. His vital signs are stable, and he has no other visible injuries. Which of the following is the most likely diagnosis?
A: Ruptured spleen
B: Ruptured liver
C: Ruptured pancreas
D: Hematoma in the rectus muscle
E: Ruptured duodenum