**Core Concept**
Meckel Diverticulum is a congenital anomaly resulting from the incomplete closure of the vitelline duct, which is a communication between the yolk sac and the primitive midgut during embryonic development. This remnant can lead to various complications, including gastrointestinal bleeding, obstruction, and diverticulitis.

**Why the Correct Answer is Right**
The vitelline duct typically obliterates and disappears by the 6th week of gestation. However, in some cases, its remnants persist, forming a Meckel Diverticulum, which is usually located on the antimesenteric border of the ileum, approximately 60 cm from the ileocecal junction. The diverticulum is a true diverticulum, containing all layers of the intestinal wall, and is often connected to the intestinal lumen by a narrow stalk.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Meckel Diverticulum is not a remnant of the omphalomesenteric duct, which is a different embryonic structure.
**Option B:** This option is incorrect because Meckel Diverticulum is not a remnant of the appendix, although both structures arise from the embryonic midgut.
**Option C:** This option is incorrect because Meckel Diverticulum is not a remnant of the pancreatic or biliary ducts, which are derived from the endodermal foregut.

**Clinical Pearl / High-Yield Fact**
The rule of twos is a useful mnemonic to remember the characteristics of Meckel Diverticulum: it occurs in 2% of the population, is usually 2 inches in length, and is located 2 feet from the ileocecal junction.

**Correct Answer: B. Omphalomesenteric duct.