## Core Concept
The patient's presentation of syncope during defecation accompanied by gross bleeding suggests a condition that leads to acute blood loss. This scenario points towards a lower gastrointestinal bleed, likely from a colorectal source. The recent negative fecal occult blood test (FOBT) does not rule out a significant bleed, especially if it was performed 3 months prior.

## Why the Correct Answer is Right
The likely colonoscopic finding in this case is **Diverticulosis**, particularly if one of the options directly mentions diverticula or a condition commonly associated with diverticula. Diverticulosis is a condition where small, bulging pouches (diverticula) develop in the digestive tract, most commonly in the colon. It is a common cause of significant lower gastrointestinal bleeding, especially in older adults. The bleeding is often sudden, painless, and large enough to cause hemodynamic instability, which could explain the patient's syncope.

## Why Each Wrong Option is Incorrect
- **Option A:** This option would be incorrect if it described a finding not typically associated with acute lower GI bleeding in the elderly, such as a polyp or early cancer, which might not cause such a sudden and significant bleed.
- **Option B:** Similarly, if this option suggested another cause not commonly linked with acute bleeding in this age group, like inflammatory bowel disease, it would be less likely given the acute presentation and lack of other symptoms like diarrhea or weight loss.
- **Option C:** If this option described a condition not directly related to the clinical scenario, such as ischemic colitis, it might not fit as well given the specific context of bleeding during defecation.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **diverticulosis** is a common cause of painless, large-volume hematochezia in elderly patients. The fact that the FOBT was negative 3 months prior does not rule out diverticulosis as the cause of the current bleed, as the test may not detect intermittent or rapid blood loss.

## Correct Answer: D. Diverticulosis.