**Core Concept**
The question tests the understanding of hematopoiesis, specifically the origin of progenitor hematopoietic stem cells. Hematopoiesis is the process by which all blood cells are produced, and it begins with **hematopoietic stem cells**. These cells have the ability to differentiate into all blood cell types.

**Why the Correct Answer is Right**
Progenitor hematopoietic stem cells originate in the **yolk sac** during embryonic development, later transitioning to the **liver** and finally to the **bone marrow**. The yolk sac is the first site of blood cell production, providing the necessary environment for the development of hematopoietic stem cells.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because, although the liver is a site of hematopoiesis, it is not the initial origin of progenitor hematopoietic stem cells.
**Option B:** Incorrect as it is not specified, but assuming it refers to another incorrect location.
**Option D:** Incorrect as it is also not specified, but would be an incorrect location for the origin of progenitor hematopoietic stem cells.

**Clinical Pearl / High-Yield Fact**
Remember that hematopoiesis transitions from the yolk sac to the liver and finally to the bone marrow during development. This knowledge is crucial for understanding various hematological disorders.

**Correct Answer:** D. Yolk sac