A 4-year-old boy presents to the emergency department with right lower quadrant pain, nausea, and anorexia. On physical examination, his bowel sounds are absent, and he has marked tenderness in the right lower quadrant with guarding. The remainder of the abdominal exam is negative. Laboratory values reveal a leukocytosis with a left shift. What is the most likely initiating event for his acute condition?
(A) Lymphoid hyperplasia
(B) Fecalith
(C) Parasitic infection
(D) Enlarged mesenteric lymph nodes
(E) Foreign body ingestion