**Core Concept**
Meckel's diverticulum is a congenital anomaly resulting from the incomplete closure of the vitelline duct, leading to a small, true diverticulum of the ileum. It is a remnant of the embryonic yolk sac.

**Why the Correct Answer is Right**
Meckel's diverticulum contains gastric or pancreatic tissue in 50-70% of cases, leading to complications such as bleeding, obstruction, or diverticulitis. The presence of ectopic tissue is due to the incorporation of the vitelline duct into the ileal wall during embryonic development. The ectopic tissue can lead to the production of gastric acid, causing mucosal ulceration and bleeding.

**Why Each Wrong Option is Incorrect**
**Option A:** Meckel's diverticulum is always located on the antimesenteric border of the ileum. This is incorrect because Meckel's diverticulum can be located on either the antimesenteric or mesenteric border of the ileum.
**Option B:** Meckel's diverticulum is a false diverticulum. This is incorrect because Meckel's diverticulum is a true diverticulum, containing all layers of the intestinal wall.
**Option C:** Meckel's diverticulum is a complication of Crohn's disease. This is incorrect because Meckel's diverticulum is a congenital anomaly, not a complication of Crohn's disease.

**Clinical Pearl / High-Yield Fact**
The "2-2-1 rule" can be used to remember the likelihood of complications from Meckel's diverticulum: 2% of the population has Meckel's diverticulum, 2% of those will have complications, and 1 in 300 patients with complications will have intestinal obstruction.

**Correct Answer: B. Meckel's diverticulum is a false diverticulum.**