**Core Concept**
The clinical presentation of a 9-month-old child with excessive crying, a right iliac fossa sausage-shaped lump, and blood in stools is suggestive of intussusception, a condition where a part of the intestine invaginates into another, leading to bowel obstruction and potential ischemia.

**Why the Correct Answer is Right**
Intussusception is a medical emergency requiring prompt treatment to prevent bowel necrosis. The correct treatment involves reducing the intussusception and relieving the obstruction. This can be achieved through air enema reduction, which involves administering air under pressure to push the invaginated segment back into its normal position. Air enema reduction is a preferred method due to its non-invasive nature and high success rate.

**Why Each Wrong Option is Incorrect**
* **Option A:** Surgery is typically reserved for cases where air enema reduction fails or is contraindicated, such as in the presence of bowel perforation or significant bowel ischemia. It is not the primary treatment for intussusception.
* **Option B:** Antibiotics are not effective in treating intussusception, as they do not address the underlying mechanical obstruction. They may be used to treat potential secondary infections.
* **Option C:** Nasogastric suction is not indicated in intussusception, as it does not relieve the obstruction and may worsen the condition by causing aspiration of intestinal contents.

**Clinical Pearl / High-Yield Fact**
In cases of intussusception, the "triad" of symptoms often includes abdominal pain, bloody stools, and an abdominal mass. However, not all patients present with this classic triad, and a high index of suspicion is required to diagnose this condition.

**Correct Answer:** C.