**Core Concept**
Rectal painful bleeding, particularly when self-limiting, can be caused by various conditions, but a common cause is a rectal ulcer. This condition often presents with rectal pain and bleeding, especially during defecation.

**Why the Correct Answer is Right**
The most likely cause of a self-limiting rectal painful bleeding is a rectal ulcer, which is often associated with anal fissure. The pain is due to the stretching of the anal sphincter muscles during defecation, leading to ischemia and subsequent ulceration. The anal sphincter muscles are richly innervated with pain receptors, explaining the severe pain associated with this condition. The bleeding is usually bright red and can be stopped by applying gentle pressure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant as it does not describe a condition that typically causes self-limiting rectal painful bleeding.
**Option B:** This option might be a distractor, but it is less likely to be the correct answer as proctitis is an inflammation of the rectum and is not typically self-limiting.
**Option C:** This option is incorrect as hemorrhoids are a common cause of rectal bleeding, but the bleeding is usually not painful and is not self-limiting.

**Clinical Pearl / High-Yield Fact**
A classic exam question trap is to confuse rectal ulcers with anal fissures. Remember that anal fissures are a tear in the anal mucosa and are not usually associated with bleeding, whereas rectal ulcers are a common cause of painful bleeding during defecation.

**Correct Answer: A. Anal fissure**