What is the treatment of choice for a child with intussusception?

A. Air or Barium enema: This is both diagnostic and therapeutic. The enema can reduce the intussusception by relieving the telescoping of the bowel. B. IV fluids until spasm subsides: While IV fluids are used to manage dehydration, they do not resolve intussusception. C. Immediate surgery: Surgery is reserved for cases where enemas are unsuccessful or complications like perforation occur. D. Gastric gavage: This is not related to treating intussusception and does not address the underlying issue.