**Core Concept**
Rectal bleeding in toddlers is a common symptom that requires a careful evaluation to identify the underlying cause. The differential diagnosis for rectal bleeding in this age group includes benign conditions such as intussusception, anal fissures, and rectal foreign bodies, as well as more serious conditions like rectal polyps, inflammatory bowel disease, and rectal cancer.

**Why the Correct Answer is Right**
Intussusception is a medical emergency characterized by the telescoping of a portion of the intestine into the adjacent segment, leading to bowel obstruction and ischemia. The classic presentation of intussusception includes sudden onset of abdominal pain, vomiting, and passage of a "currant jelly" stool, which is blood mixed with mucus. In toddlers, intussusception is often caused by a lead point such as a Meckel's diverticulum or a lymphoid hyperplasia. The diagnosis of intussusception is typically made using ultrasound, and treatment usually involves air enema reduction or surgical intervention.

**Why Each Wrong Option is Incorrect**
**Option A:** Anal fissures are a common cause of painful rectal bleeding in infants and toddlers, but they typically present with a single episode of bright red blood on the stool or on the diaper.
**Option B:** Rectal polyps are rare in toddlers and are usually associated with a family history of familial adenomatous polyposis (FAP).
**Option C:** Rectal cancer is extremely rare in toddlers and is usually associated with a palpable abdominal mass or a history of abdominal radiation.

**Clinical Pearl / High-Yield Fact**
The "3 Ps" of intussusception are pain, pallor, and passage of a currant jelly stool, which are classic signs of this condition in toddlers.

**Correct Answer: C. Intussusception**